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Home My WebLink AboutF216 (LCB) WATERSHED( ( Binkley 8c Barfield, Inc., Consulting Engineers 1710 Seamist Drive 0 Houston, Texas 77008-3189 (713) 869-3433 FAX (713) 869-6702 Mr. Burton Johnson, P.E. Harris County Flood Control Di strict 9900 Northwest Freeway Houston, TX 77092 January 27, 2000 Re: Watershed Study for the Little Cedar Bayou watershed Project Identification No. F216-00-00-Y001 Dear Mr. Johnson: We are submitting our rep011, which describes the details, methods. results, and conclusions reached in the above referenced study. As discussed in the report, the addition of linear detention to Little Cedar Bayou upstream of SH 146 can produce a substantial flood control benefit, without adverse effects to the Little Cedar Bayou or adj oining areas. All computer files used in this study are included on the CD in Attachment 1 to this report. Additional copies of the CD are available on request. If we can be of further service, or if you require additional information, please call. Sincerely, BINKLEY & BARFIELD, INC. Consulting Engineers ft/.7./~ John G. Fowler, P.E. Senior Project Manager Houston and Dallas TABLE OF CONTENTS ( I. SUMMARY ....................................................................................... l II. INTRODUCTION ............................................................................... 2 A. AUTHORIZATION ......................................................................... 2 B. PURPOSE AND SCOPE .................................................................. 2 III. WATERSHED CHARACTERISTICS ....................................................... 3 A. EXISTING CONDITIONS ................................................................ 3 B. DEVELOPMENT ........................................................................... 3 C. UTILITIES ................................................................................... 4 D. PRIOR STUDIES ........................................................................... 4 IV. CRITERIA FOR PROPOSED CHANNEL IMPROVEMENTS ...... : ................. 6 V. METHOD OF ANALYSIS .................................................................... 7 ( VI. EXISTING CONDITIONS ..................................................................... 8 A. EXISTING MODELS ...................................................................... 8 B. UPDATED BASE MODELS ............................................................. 9 VII . PROPOSED PLAN ............................................................................ 11 A. PROPOSED CHANNEL IMPROVEMENTS ........................................ 11 B. PROPOSED MODELS ................................................................... 11 C. COMPARISON OF EXISTING AND PROPOSED CONDITIONS ............. 12 D. ULTIMATE DEVELOPMENT CONDITIONS ..................................... 13 E. COST ESTIMATES ...................................................................... 14 VIII. CONCLUSIONS ............................................................................... 16 ( L...-.-------Binkley & Barfield, Inc. Consulting Engineers --------.J LIST OF EXlllBITS ( EXHIBIT 1 ................................................................................. Vicinity Map EXHIBIT 2 ...................................................................... Project Location Map EXHIBIT 3 ............................................................................ Utility Schematic EXHIBIT 4 ............................ Water Surface Profiles: Existing vs. Corrected Existing EXHIBIT 5 ..................... Water Surface Profiles: Corrected Existing vs. Updated Base EXHIBIT 6 ................. Water Surface Profiles: Updated Base vs. Proposed up to SPRR EXHIBIT 7 ....................................................................... 100 Year Flood Plain EXHIBIT 8 ................... Water Surface Profiles: Updated Base vs. Proposed up to Sens EXHIBIT 9 ........................ Water Surface Profiles: Ultimate Development Conditions APPENDICES APPENDIX A ............................... Physical Characteristics and Unitgraph Parameters APPENDIX B ......................................................... Tabulated Model Comparison Attachment B-1 .............................................. Existing vs. Corrected Existing Attachment B-2 ........................................ Corrected Existing vs . Updated Base Anachment B-3 .................................... Updated Base vs. Proposed up to SPRR ( Attachment B-4 ...................................... Updated Base vs. Proposed up to Sens Attachment B-5 ...... Water Surface Elevation Comparison Between Proposed Models Attachment B-6 .............................................. Updated Base vs. Ultimate Base Attachment B-7 ........................................ Ultimate Base vs. Ultimate Proposed APPENDIX C ........................................................................... Cost Estimates ATTACHMENTS Attachment 1 ..................................... Compact Disk Containing the Following Files : Existing Models from HCFCD F21600FH.FCD ............................................. HCFCD Flood Hazard HEC-2 Model F21600FH.FEM ............................................. FEMA Flood Hazard HEC-2 Model F21600FW.FEM .................................................. FEMA Floodway HEC-2 Model F2 1600SO.FCD .............................................................. Routing HEC-2 Model F216-10.FCD .................................................................. 10 Year HEC-1 Model F216-100.FCD .............................................................. 100 Year HEC-1 Model ( ii L----------Binkley & Barfield, Inc. Consulting Engineers ----------J I Corrected Existing Models l F216REV .FCD ................................. Corrected Existing Flood Hazard HEC-2 Model lOREV .BBI ............................................ Corrected Existing 10 Year HEC-1 Model lOOREV.BBI ......................................... Corrected Existing 100 Year HEC-1 Model Updated Base Models JKFNEW6.BBI .............................................. Updated Flood Hazard HEC-2 Model RTJKF6.BBI ............................................................ Base Routing HEC-2 Model 10JKF6.IH1 ............................................................. 10 Year Base HEC-1 Model 100JKF6.IH1 .......................................................... 100 Year Base HEC-1 Model Proposed Models Improvements between SH 146 and SPRR SEDIM2.BBI ............................................... Proposed Flood Hazard HEC-2 Model RTSEDIM2.BBI. .................................................. Proposed Routing HEC-2 Model 10SED2. IH 1 ....................................................... Proposed 10 Year HEC-1 Model ( 1 OOSED2. IH 1 .................................................... Proposed 100 Year HEC-1 Model Improvements between SH 146 and Sens Road SEDIM3.BBI ............................................... Proposed Flood Hazard HEC-2 Model RTSEDIM3.BBI. .................................................. Proposed Routing HEC-2 Model 1 OSED3. IH 1 ....................................................... Proposed 10 Year HEC-1 Model 100SED3.IH1 .................................................... Proposed 100 Year HEC-1 Model Ultimate Models ULTBASE.BBI ....................................... Ultimate Base Flood Hazard HEC-2 Model ULTPSED.BBI ................................. Ultimate Proposed Flood Hazard HEC-2 Model lOULT.IHl .................................................. Ultimate Base 10 Year HEC-1 Model lOOUL T. IH 1 ................................... : ........... Ultimate Base 100 Year HEC-1 Model 10ULTP.IH1 ........................................... Ultimate Proposed 10 Year HEC-1 Model lOOULTP.IHl ........................................ Ultimate Proposed 100 Year HEC-1 Model ( 111 '-----------Binkley & Barfield, Inc. Consulting Engineers ----------' ( ( I. SUMMARY The Linle Cedar Bayou watershed is located in southeast Harris County within the city limits of the City of La Pone, Texas and includes 3.2 square miles of land that is approximately half developed. There is an even mixture of commercial and residential development within the watershed, with the bayou running through the more densely developed areas of La Porte. Linle Cedar Bayou exists as a narrow, winding, earthen channel between SH 146 and West Barbours Cut Boulevard. Downstream of SH 146, pans of the channel have been straightened and improved with concrete slope paving. Upstream of West Barbours Cut Boulevard, the bayou exists as a relatively straight earthen channel resembling an oversized roadside ditch . Little Cedar Bayou has a history of flooding especially in the reaches upstream of SH 146. Most of the bridge crossings serve as restrictions to the flow, especially at SH 146 where debris collects on a regular basis. This study and analysis of the Little Cedar Bayou watershed revealed that a definite flood control benefit could be gained from implementing channel improvements upstream of SH 146. The proposed improvements that were analyzed in this repon included a linear detention pond between SH 146 and "B" Street, lowering the flow line upstream of SH 146, and reshaping the side slopes to 3: 1. Two proposed projects were analyzed. The first project included improvements up to the Southern Pacific Railroad. The second project included improvements up to Sens Road. Construction of the proposed improvements will result in an overall lowering of the 100 year water surface elevation along the entire length of the bayou and in a reduction in the 100 year flood plain width within the Linle Cedar Bayou watershed. The 100 year water surface elevation will be reduced by as much as 1.46' and the 100 year top width will be decreased by as much as 3,354' at West Barbours Cut Boulevard. The proposed improvements have been estimated to cost approximately $2 million for improvements up to the Southern Pacific Railroad, and an additional $1.2 million, for a total of $3.2 million, for improvements up to Sens Road. This analysis, based on standard techniques and rainfall patterns, shows that construction of the proposed improvements will result in a significant flood control benefit, while causing no adverse effects to the Little Cedar Bayou watershed or adjoining areas. .___ _________ Binkley & Barfield, Inc. Consulting Engineers _________ __. ( ( ( II. INTRODUCTION A. AUTHORIZATION The Harris County Flood Control District engaged the services of Binkley & Barfield, Inc. (BBI) to perform a watershed study on Little Cedar Bayou and affected areas in July 1998. Notice-to-Proceed on the first three of seven tasks was given on July 28, 1998 based on Purchase Order No. 0350263. The last four of seven tasks was authorized on October 28, 1998 by Purchase Order Nos. 0350263 and 0374098. B. PURPOSE AND SCOPE The purpose of this report is to present the methodology and results of a study of Little Cedar Bayou, which was performed to update the Harris County Flood Control District's (HCFCD) plan for the Little Cedar Bayou Watershed. This study was initially authorized in conjunction with the Harris County Public Infrastructure Department's plans for improvements to Bay Area Boulevard. This report details the study of the watershed on Little Cedar Bayou and describes the steps taken in analyzing the effects of different proposed improvements to the watershed and bayou. As identified by HCFCD's Action Plan, the scope of this project included: 1. Identify and quantify flooding problems in the Little Cedar Bayou watershed associated with existing, anticipated, and ultimate development. 2. Recommend a plan to eliminate structural flooding up to the 100 year event along Little Cedar Bayou for existing, anticipated, and ultimate development. 3. Identify the details associated with the implementation of the plan. 4. Identify and consider other drainage and flood control needs in the area, including Little Cedar Bayou watershed and adjacent areas. 5. Identify the benefits and impacts derived for the area. 6. Produce a report suitable as a guide for the preparation of construction plans. 7. Produce a report able to support permit requests associated with implementation of the project. Items 1, 2, 3, 5, 6, and 7, above, are addressed directly in this report. In order to address Item 4, the results of this study were used as input data for a drainage feasibility study for the Harris County Public Infrastructure Department in conjunction with roadway improvements to Bay Area Boulevard in the A 104-07-00 watershed. 2 '-----------Binkley & Barfield, Inc. Consulting Engineers -----------~ ( ( III. WATERSHED CHARACTERISTICS A. EXISTING CONDITIONS The Little Cedar Bayou watershed (HCFCD Unit F216-00-00) is located in southeast Harris County in Precinct 2. See Vicinity Map, Exhibit 1. The watershed is contained entirely within the city limits of the City of La Porte, Texas and covers approximately 3.2 square miles. See Project Location Map, Exhibit 2. Little Cedar Bayou exists as a narrow, winding, earthen channel upstream of SH 146 to West Barbours Cut Boulevard. Downstream of SH 146, portions of the bayou have been improved with concrete slope paving. Upstream of West Barbours Cut Boulevard, the bayou is a straight earthen channel that looks like an oversized roadside ditch running parallel to West Barbours Cut Boulevard. Little Cedar Bayou drains from its headwaters at Sens Road down to its mouth at Galveston Bay. It flows in an easterly direction from Sens Road and runs parallel to West Barbours Cut Boulevard. About 1 ,300' east of the Southern Pacific Railroad (SPRR), it turns south and crosses under West Barbours Cut Boulevard. Little Cedar Bayou runs in a south- southeasterly direction from West Barbours Cut Boulevard to Galveston Bay. Little Cedar Bayou drains most of the densely developed areas of the City of La Porte. The natural terrain of the watershed is relatively flat with a slight southeasterly slope towards Galveston Bay. Little Cedar Bayou has a history of flooding especially upstream of SH 146. Major channel improvements have already been implemented downstream of SH 146. B. DEVELOPMENT The Little Cedar Bayou watershed consists of three subareas: LCB-1A, LCB-1B, and LCB-2. Exhibit 2 shows the three subareas of Little Cedar Bayou. As stated earlier, Little Cedar Bayou drains most of the densely developed areas, but the watershed is not fully developed. LCB-2, the subarea that borders Galveston Bay, is the most developed subarea in the watershed. It is more than 60% developed with most of the development being residential in nature. The land immediately adjacent to Little Cedar Bayou in this subarea is primarily undeveloped to the north with some residential development occurring at the mouth to the Bay and commercial development occurring near SH 146. To the south, the land consists of park area. The remaining undeveloped areas within this subarea are allocated for residential and public use based on the City of La Porte Land Use Plan. LCB-1B is the largest subarea within the watershed. It is almost half developed at 49%. The existing development is evenly divided between industrial/commercial and residential/park areas. The area immediately adjacent to the bayou is primarily undeveloped with a few exceptions. A residential area is just east of the bayou between SH 146 and West Main Street, also known as Spencer Highway. At Spencer Highway, some commercial development abuts and may even encroach on Little Cedar Bayou. A park lies just east of the bayou between Spencer Highway and West Barbours Cut Boulevard, and along West 3 .._ _________ Binkley & Barfield, Inc. Consulting Engineers ----------' ( ( ( Barbours Cut Boulevard some industrial development exists to the south of the bayou. The remaining undeveloped areas are mainly allocated for industrial or commercial uses based on the City of La Porte Land Use Plan. The western most subarea, LCB-lA, is the smallest and least developed subarea at 30%. Most of the area is currently residential in nature with a few industrial areas. The area immediately adjacent to the bayou is undeveloped, except at Sens Road where there is some residential development. Based on the City of La Porte Land Use Plan, the remaining undeveloped land is allocated for an equal amount of commercial/industrial uses and residential uses. C. UTILITIES Utilizing plans obtained from the City of La Porte and private utility companies, the locations of the existing utilities along Little Cedar Bayou were determined. Most of the utilities cross the bayou at bridge crossings either within or near the roadway right-of-way. However, a few utilities do not cross at roadway bridges. See Exhibit 3, Utility Schematic. There is a 6" sanitary sewer force main that crosses very near the mouth in the vicinity of Bayshore Drive. Approximately 200 feet upstream of SH 146 a 10" sanitary sewer crosses Little Cedar Bayou. This line is exposed and is clearly visible. Immediately upstream of the 10 " sanitary sewer a storm sewer outfalls from the west banlc A 12" sanitary sewer crosses under Little Cedar Bayou within the right-of-way of "F" Street. Within the right-of-way of "B" Street, a water line crosses Little Cedar Bayou. This line is also exposed and clearly visible. A 12" water line crosses under Little Cedar Bayou near "A" Street. According to record drawings, it is approximately 3 feet under the flow line. Reliant Energy Entex has facilities along Little Cedar Bayou. These facilities all cross the bayou near street crossings. A 4" intermediate pressure (1. P.) steel line crosses at South Broadway along the west side, and a 6" I.P. steel line crosses at West "K" Street on the north side. A 2" I.P. steel line crosses between Spencer Highway and West "A" Street, and another 2" I.P. steel line crosses between Spencer Highway and West Polk Street. A 6" I.P. steel line crosses at West Barbours Cut Boulevard on the south side. Southwestern Bell Telephone has facilities crossing Little Cedar Bayou at West Fairmont Parkway on the north side, Spencer Highway on the north side, and at Sens Road on the east side. Reliant Energy HL&P does not have any buried facilities that cross Little Cedar Bayou. D. PRIOR STUDIES Several studies have been completed that cover the entire Little Cedar Bayou watershed. These studies include the City of La Porte Master Drainage Plan prepared by O'Malley & Clay, Inc., the Flood Insurance Study (FIS) prepared by the U.S. Army Corps of Engineers, 4 "-----------Binkley & Barfield, Inc. Consulting Engineers _________ _... ( ( ( and Study of Flood Control Improvements for Linle Cedar Bayou prepared by Espey, Huston & Associates, Inc. (EH&A). The latest study of Little Cedar Bayou was the EH&A report which was completed in September 1989. The EH&A report served as an update to the FIS, incorporating channel improvements that had been constructed since the completion of the FIS. The EH&A report addressed existing flooding problems along Little Cedar Bayou and presented recommendations for an interim and ultimate project for handling flooding problems. The EH&A report recommended an interim project consisting of improving approximately 10,700 linear feet of channel and modifying six bridges, and also recommended an ultimate project, consisting of a 24 acre detention facility and the diversion of 270 acres along the northern end of the watershed into Galveston Bay. 5 L-----------Binkley & Barfield. Inc. Consulting Engineers -----------' ( ( IV. CRITERIA FOR PROPOSED CHANNEL IMPROVEMENTS The basic criteria for improvement to a watershed is that the improvement must produce a cost-effective flood control benefit with no adverse effects to other parts of the watershed or adjoining areas. The goal is to improve the channel without increasing the water surface elevations for any frequency of storm event which is not entirely contained within the channel banks. The criteria set forth by HCFCD states that the proposed improvements identified in this report should coincide with the optimum plan for the Linle Cedar Bayou watershed. This study should consider, but not be limited to, the components identified in the EH&A report. Harris County Precinct 2 follows the same criteria set by HCFCD. Their primary concern was that this study could help answer drainage questions that had arisen on roadway improvement projects at Bay Area Boulevard and at Sens Road. The City of La Porte assisted in determining areas that could be used for linear detention. Members of the Engineering Staff of the City of La Porte provided BBI with information regarding acceptable detention areas, where land could be purchased, or where land had already been purchased for the proposed improvements. This entire study was coordinated with HCFCD, Harris County Precinct 2, and the City of La Porte. 6 '-----------Binkley & Barfield, Inc. Consulting Engineers ----------~ ( ( ( V. METHOD OF ANALYSIS The basic modeling methodology included using HEC-1 to calculate the hydrographs and peak flows within the watershed for each of the channel reaches, while HEC-2, was used to determine the water surface profiles in each channel reach corresponding to peak flows calculated by HEC-1 . The method of analysis was consistent for all models that were run and compared. The following steps were taken in the analysis: 1. The routing HEC-2 model was updated with survey sections or proposed sections and run. The storage discharge relationships were obtained from the Tape7 output of the routing model. 2. The HEC-1 models were updated with the storage discharge relationships taken from the Tape7 output. 3. HEC-1 was run to determine the updated flows. 4. The updated flows and channel sections were added to the effective HEC-2 model; HEC-2 was run to determine the water surface elevation and top width. Using the above methodology, existing HEC-1 and HEC-2 models were revised and updated to create a base model reflecting existing conditions. HEC-1 and HEC-2 models were similarly created to produce models reflecting proposed conditions. The output from the base model and proposed models was compared to determine the effects of the proposed improvements. 7 .._ _________ Binkley & Barfield, Inc. Consulting Engineers -----------J ( ( ( VI. EXISTING CONDITIONS A. EXISTING MODELS At the commencement of this project, BBI received seven HEC models from HCFCD. There were four HEC-2 models and three HEC-1 models. To determine which models should be used for this study, the models were compared and contrasted to the revised existing models in the EH&A study. The flood hazard model that was chosen as the starting model for this srudy waS almost identical to the revised existing flood hazard model in the EH&A srudy with the following exceptions: 1. The Lichliter Jameson & Associates model of the Spencer Highway Bridge replacement had been incorporated. 2. The overall reach length was 3.5 feet longer because of the addition of the Spencer Highway Bridge. 3. There were two additional QT cards present near the Spencer Highway Bridge; these QT cards contained Q's that did not agree with the other QT cards in the model. The physical characteristics and unitgraph parameters used in the existing HEC-1 models are included in Appendix A. These characteristics and parameters were checked and verified, except for the values of TC+R for LCB-1A, which were revised to reflect a DLU value greater than 18% using the following equation: • 0.706 rc + R = 4295 nru-'"' nee-'"' }'-JS The corrected value of TC + R changed from 6.46 in the existing model to 14.4 7 in the corrected existing model for LCB-1A. The R-value also changed from 5.64 to 13 .65 in the corrected existing model for LCB-1 A. These values were put into the existing HEC-1 models to create the corrected existing HEC-1 models. The corrected existing peak flows were calculated from a HEC-1 run using the revised TC + R values, and the flow for LCB-1 A was reduced by 329 cfs. The corrected existing flows were added to the existing HEC-2 model to become the corrected existing HEC-2 model. This corrected existing model had lower water surface elevations by as much as 1 . 04' and narrower top widths by as much as 671 ' than the existing model. The tabulated results are included in Appendix B, Attachment B-1. Exhibit 4 shows a comparison of the 10 and 100 year water surface profiles between the existing model and the corrected existing model. The corrected models were used for comparisons and evaluations of the potential flood control benefits to be derived from the proposed detention and channel improvements. The corrected models that were used for this study were the flood hazard model, F216REV . FCD, and the 10 and 100 year HEC-1 models, 10REY.BBI and 100REV.BBI, respectively. These files are included on the CD in Attachment 1. 8 .......__ _________ Binkley & Barfield, Inc. Consulting Engineers -----------' ( ( ( :. B. UPDATED BASE MODELS The corrected existing HEC-1 models mentioned in the previous section were updated to reflect the most current physical characteristics and unitgraph parameters of the watershed. The physical characteristics were updated using the latest aerial photos, survey, maps, and plans. The updated base models used the most current watershed boundaries, which were moved in slightly from the north compared to the corrected existing model's boundaries. The current northern boundaries were taken from a set of plans for channel Fl01-00-00. The new boundaries caused the subareas, LCB-1A and LCB-1B, to be slightly smaller in area compared to the corrected existing model. Most of the other physical characteristics for the updated base model were very similar to the corrected existing model with the exception of the channel slope for LCB-1A. It was recorded as 3.54 feet per mile in the corrected existing models, but was calculated as 0.94 feet per mile from the survey data collected in 1998. See Appendix A for the physical characteristics and unitgraph parameters for the corrected existing and updated base conditions. The unitgraph coefficients were calculated from the newly updated physical characteristics of each subarea of the Little Cedar Bayou watershed. The newly calculated TC + R valu es and percentage impervious area were updated in the HEC-1 models to become the updated base models, 10JKF6.IH1 and 100JKF6.IH1, for the 10 and 100 year HEC-1 models, respectively. An additional routing reach was also included in the updated base HEC-1 models. The number of routing steps for each reach was adjusted accordingly. The corrected existing HEC-2 models mentioned in the previous section were updated to reflect the 1998 survey by Baseline Corporation. The following changes were made to the HEC-2 model: 1. The flow line at the Southern Pacific Railroad (SPRR) bridge was raised from 7' in the corrected existing model to 11' as shown in the survey from 1998. 2. The distance between the tops of banks through the 16th Street culvert was changed from 100' in the corrected existing model to 40' as observed in the field. 3. The channel sections at Spencer Highway, West Barbours Cut Boulevard, and 16th Street were updated to reflect the measurements taken in the field. 4. The eastern most span of the Spencer Highway Bridge was modeled to show that it is almost entirely blocked by a reinforced concrete pipe. 5. The survey data was added upstream of SPRR to extend the model to Sens Road. The box culvert at Sens Road was included also. With these changes incorporated, the corrected existing model became the updated base effective model, JKFNEW6.BBI. A HEC-2 routing model was created from the updated base effective model. The following changes were made to the effective model to become the routing model, RTJKF6.BBI: 1. All the ET and X3 cards were removed. 9 ..__ _________ Binkley & Bartield, Inc. Consulting Engineers ---------_..J ( ( ( 2. Manning's n-value was changed to 0.99 for the overbank areas to model the ineffective flow areas. 3. The QT cards were removed throughout the model except at the beginning of the routing reaches. 4. The QT values were adjusted to use 20, 40, 60, 80, 100, and 120% of the 100 year flow within each reach. 5 . Three reaches were used instead of two: 0-8432, 8432-11174, 11174-16821. The updated base models were used as the basis of comparison for this study . This is considered correct since these models represent the latest watershed boundaries and physical characteristics. All variables were calculated using the most recent information available. The updated base model HEC files are included in Anachment 1. 10 "----------Binkley & Bar1ield, Inc. Consulting Engineers ---------....J ( ( VII. PROPOSED PLAN A. PROPOSED CHANNEL IMPROVEMENTS The proposed channel improvements include constructing a 2,700' long linear earthen detention pond between SH 146 and Spencer Highway on the west side of the channel and lowering the flow line upstream of SH 146 to the Southern Pacific Railroad (SPRR). The location of the proposed linear detention pond was coordinated with the City of La Pone. Several field visits were made to determine which areas could be bought by the city and which areas were already owned by the City and could be made available for use. The proposed linear detention pond is a long narrow rectangle that follows the natural curvature of the bayou. It will start approximately 100 feet upstream of SH 146 and end at "B" Street. The linear detention pond will have a 225' wide bonom at the south end and will taper back to the original channel width at "B" Street. The east bank will have a 3: 1 side slope since it is part of the channel. The west bank will have a flaner 4 :1 side slope. The bonom will be cut down to the proposed flow line in order to contain the low flows and provide adequate storage to gain flood control benefits. The design of the pond would allow for park like landscaping and could serve as a recreational area during the dry season. The flow line will be lowered between SH 146 and SPRR. The proposed flow line is approximately 0.1% because the terrain is so flat. The flow line will be lowered 1.15' at Spencer Highway and 0.42' at West Barbours Cut Boulevard. The flow line at 16lh Street and SPRR matched the desired flow line elevation. An additional proposed model was run that lowered the flow line up to Sens Road. The two different proposed models will be discussed in the following section. A 20' wide concrete low flow is proposed under Spencer Highway between the bents to meet the desired flow line elevation. Also, at Spencer Highway, the reinforced concrete pipe, which blocks the eastern most span, was assumed to remain in place since very linle difference was seen in water surface elevation with its removal (±0.05'). Accompanying the lowering of the flow line, the side slopes upstream of SH 146 will be regraded to achieve 3:1 slopes. The bonom widths remain the same as the existing channel bonom widths, except in a few places where the bonom width was brought in slightly to keep the top of banks from being too far apart. B. PROPOSED MODELS For this study, two proposed models were created. Both models reflect the proposed conditions described above, but the first model extends the lowered flow line and 3: 1 side slopes to SPRR, while the second model extends the improvements all the way to Sens Road. This section will describe in detail the techniques used to model the proposed conditions. 11 L...----------Binkley & Bartield, Inc. Consulting Engineers -----------J ( ( ( In order to determine the size of the linear detention pond, a target value of $1 million was set for excavation. This would keep the overall construction costs near $2 million. Using an estimate of $5 per cubic yard, the amount of earth that could be excavated was calculated to be 200,000 cubic yards. Using the Channel Improvement (CI) cards in HEC-2 to model the proposed improvements, a trial and error method was used to reach the desired goal of 200,000 cubic yards of excavation. The construction cost estimate includes excavation of the proposed pond to a depth of 1' to 2' below the bottom elevation used in the models . This over excavation will insure that sufficient storage volume remains in the pond after siltation and buildup in the pond bottom. The lowered flow line and 3: 1 side slopes were modeled using CI cards. The proposed improvements were centered on the existing centerline of the channel except at Spencer Highway. A parking lot encroaches on the bayou from the east downstream of Spencer Highway. The proposed channel section through this area held the east top of bank constant, and the straightening and lowering of the channel was achieved to the west. Upstream of Spencer Highway a building encroaches on the bayou from the west, so the west top of bank was held constant through this area. The straightening and lowering of the channel was done to the east to achieve the 3: 1 side slopes and desired fl ow line. C. COMPARISON OF EXISTING Al\TD PROPOSED CONDITIONS The first comparison was between the updated base model and the corrected existing model to show the differences in existing conditions between 1989 and 1999. The peak flo ws generated by the updated base HEC-1 model were lower than the corrected existing peak flows by as much as 115 cubic feet per second (cfs) between 16th Street and SPRR. The updated base peak flows were greater than the corrected existing flows by as much as 182 cfs at SH 146. The updated base model had 100 year water surface elevations that fluctuated between 0. 97' higher at SH 146 to 0.51' lower at SPRR compared to the corrected existing model. See Appendix B, Attachment B-2 for the tabulated results and Exhibit 5 fo r the water surface profiles. The two proposed models were both compared to the updated base model. The peak fl ows for the proposed models were identical. The proposed peak flows were as much as 21 cfs lower and 2 cfs higher than the updated base model peak flows. The proposed model with improvements up to SPRR was compared first. The 100 year water surface elevation was decreased the entire length of the bayou with the largest decrease of 1.46' occurring downstream of West Barbours Cut Boulevard. See Exhibit 6 for the water surface profiles. The top width was decreased by as much as 3,354' at West Barbours Cut Boulevard. Exhibit 7 shows the existing and proposed 100 year flood plain. There were a few increases in top width along the bayou; however, the water was contained within the linear detention pond or within the channel banks. See Appendix B, Attachment B-3 for the tabulated results. The proposed model with improvements up to Sens Road was compared to the updated base model and to the other proposed model. This proposed model produced the exact same peak fl ows as the first proposed model. This model also had identical water surface elevations as 12 ..._ _________ Binkley & Barfield, Inc. Consulting Engineers -----------' ( ( ( the first proposed model up to SPRR. Upstream of SPRR the water surface elevation was less than the updated base model and was as much as 0. 31 ' lower than the first proposed model for the 100 year water surface elevation at Sens Road. Exhibit 8 shows the water surface proflles for the 10 and 100 year events. As with the first proposed model, the top widths were decreased the entire length of the bayou, and in the few places it was increased, it was contained within the channel or pond. Upstream of SPRR the top widths were reduced even more than in the first proposed model by more than 900' downstream of Sens Road. The tabulated results are included in Appendix B, Attachments B-4 and B-5. D. ULTIMATE DEVELOPMENT CONDITIONS Ultimate development conditions models, or ultimate models, were created to determine whether the proposed channel improvements to Linle Cedar Bayou will provide flood control benefits once the watershed is fully developed. Both an ultimate base model and an ultimate proposed model were created. Using the City of La Porte Land Use Plan map, the amount of impervious area was calculated for each subarea of the Little Cedar Bayou watershed assuming the area was completely developed. The percentage of impervious area was determined by calculating the area of each type of land use within each subarea and multiplying the area by the respective runoff coefficient. The runoff coefficients used were adapted from the "Storm Water Management Handbook for Construction Activities", by Harris County/Harris County Flood Control District and City of Houston, Table 2.1 TYPICAL "c" VALUES, page Appendix A-7. The runoff coefficients for each type of land use are listed below: + Parks 0.25 + Low-density residential 0.35 + Mid to High-density residential 0.50 + Commercial (LCB 1A) 0. 70 + Commercial/Industrial 0. 80 + Commercial (LCB !B)/Business (LCB 2) 0.85 + lnd ustrial 0. 90 + Business (LCB 1B)/Commercial (LCB 2) 0.95 The physical characteristics and unitgraph parameters for each subarea of Linle Cedar Bayou were calculated for the ultimate development conditions. See Appendix A . The only difference between the updated base physical characteristics and the ultimate characteristics was that the ultimate characteristics assumed 100% development (DLU = 100). This changed the unitgraph parameters significantly from the updated base parameters. The ultimate base HEC-1 models were created by adding the newly calculated TC + R parameters and the percent impervious. The ultimate base peak flow s were calculated from the HEC-1 run and added back to the ultimate base HEC-2 model. A comparison between the updated base model and the ultimate base model shows an overall increase in peak flows, by as much as 600 c .f.s., for the ultimate base model. This increase in peak flow translates into an overall increase in 100 year water surface elevation for the 13 ...._ _________ Binkley & Barfield, Inc. Consulting Engineers -----------J ( ( ultimate base model. The ultimate base 100 year water surface elevation ranges from 0 . 73' to 1. 92' higher than the updated base model . See Appendix B, A nachment B-6. An ultimate development conditions proposed model, or ultimate proposed model, was created by adding the newly calculated TC + R parameters and percent impervious to the proposed HEC-1 model. The ultimate proposed peak flows were calculated from the HEC-1 run and added to the ultimate proposed HEC-2 model. The ultimate proposed model includes improvements up to the Southern Pacific Railroad only. A comparison between the ultimate base model and the ultimate proposed model shows that the proposed challl1el improvements will still provide significant flood control benefits even after the watershed is fully developed. There are no increases in 100 year water surface elevation for the ultimate proposed model the entire length of the bayou. See Exhibit 9 for the water surface profiles. The top width is decreased throughout the entire watershed except in one location where it is contained within the proposed linear detention pond. See Appendix B, Attachment B-7. The proposed improvements cause no adverse impacts to the fully developed watershed. The ultimate base HEC-2 model, ULTBASE.BBI, and the ultimate proposed HEC-2 model, ULTPSED.BBI, are included on the CD in Attachment 1, along with the ultimate HEC-1 models . The ultimate HEC-1 models for the 10 and 100 year base conditions and the 10 and 100 year proposed conditions are 1 OUL T .IH 1, 100ULT .IH 1, 1 OUL TP .IH 1, and 1 OOUL TP .IH 1, respectively. E. COST ESTIMATES Cost estimates were prepared for both of the proposed conditions. A summary table is included that compares the cost estimates from the 1989 Espey, Huston & Associates, Inc. proposed projects with the cost estimates from the proposed improvements presented in this report. The flood benefit for each proposed project is also included for two essential locations: West Barbours Cut Boulevard and Sens Road. The cost estimates are included in Appendix C. The cost estimate from 1989 does not include right-of-way acquisition costs or pipeline relocation costs. The cost estimates for the proposed conditions presented in this report include pipeline relocation costs, but no right-of-way acquisition costs. The cost estimate from 1989 has been adjusted for inflation by increasing it by 30% (3 % per year for 10 years). The total adjusted cost estimate for the 1989 proposed Ultimate Project, which includes the Interim Project, is $5.5 million, and will result in a decrease in the 100 year water surface elevation of 2.33' at West Barbours Cut Boulevard. The first proposed scenario presented in this report for improvements from SH 146 to SPRR is estimated to cost approximately $2 million, and will decrease the 100 year water surface elevation at West Barbours Cut ( Boulevard by 1.21' and by 0.15' at Sens Road. The second proposed scenario presented in this report, for improvements from SH 146 to Sens Road, is estimated to cost an additional $1.2 million, for a total of approximately $3 .2 million, and will decrease the 100 year water ~ 14 1....----------Binkley & Barfield, Inc. Consulting Engineers -----------' ( ( ( surface elevation by 1.21 ' at West Barbours Cut Boulevard and by 0.46' at Sens Road. Detailed construction cost estimates are included in Appendix C . 15 ~-----------Binkley & Barfield, Inc. Consulting Engineers -----------' ( ( ( VIII. CONCLUSIONS The proposed improvements analyzed in this report show that significant flood control benefits will be gained with the implementation of the proposed channel improvements and linear detention pond upstream of SH 146. The first project, which includes improvements up to the Southern Pacific Railroad (SPRR), will reduce the 100 year water surface elevation by more than a foot (1. 46 ') and will reduce the 100 year top width by as much as 3, 354' at West Barbours Cut Boulevard. This project is estimated to cost approximately $2 million. The second project analyzed in this report included improving the channel all the way to Sens Road. This project produced the same results up to SPRR as the first project. Upstream of SPRR the 100 year water surface elevation is reduced an additional 0 . 31' over the first project at Sens Road, and the 100 year top width is reduced more than the frrst project by more than 950' downstream of Sens Road. The second project is estimated to cost approximately $3.2 million. Table 1, following this page, summarizes the flood control benefits and construction costs of the plans discussed in this report. Based on the standard analysis techniques and rainfall panerns used in this srudy, the proposed improvements presented in this report will produce no adverse effects on the Little Cedar Bayou Watershed, or adjoining areas. 16 L..----------Binkley & Barfield, Inc. Consulting Engineers -----------' ( ( ( Table 1. Summary of Construction Costs and Flood Control Benefits Espey, Huston & Associates, Inc. 1989 Estimated Costs Interim Project $ 2,016,000.00 Inflation adjustment (1. 3) $ 2, 620,800.00 Ultimate Project $ 2,215,000.00 Inflation adjustment (1 .3) $ 2,879,500.00 Total with inflation adj. $ 5,500,300.00 Binkley & Barfield, Inc. 1999 Proposed to SPRR Estimated Costs $ 2,005 ,534.16 Reduction in 100 Reduction in 100 year WSE @ year WSE @ Sens Harbours Cut -3.39 -2.33 Reduction in 100 year WSE@ Harbours Cut -1.21 Road NA NA Reduction in 100 year WSE @ Sens Road -0.15 Proposed to Sens <tf$ 3,174,685.11 -1.21 -0.46 -i-\ 'f \,. tv~ £1--$ 'f.CrL e-~ ~c:.... $ ._.,_.... ~~ Notes: The Espey, Huston & Associates, Inc. construction estimate does not include pipeline adjustments or right-of-way acquisitions. The Ultimate Project requires that the interim project improvements be completed also. The Binkley & Barfield, Inc. construction estimates do not include right-of-way acquisitions, but they do include pipeline relocations. 17 '----------Binkley & Barfield, Inc. Consulting Engineers ------------' ( (1. u a., ~ ~ / (1. ( u (1. / <') 0 VICINI1Y MAP "' ,... "' w _J G: (1. u EXHIBIT 1 (1. Binkley & Barfield. Inc. Consulting Engineers ------------' ( ( ( <.:> 3:: 0 ..j-n_ <( ;:;> , 0 <D " <D w -' iL 0 0 I <D N I n_ ~ NOTE: ci LEGEND: WATERSHED BOUNDARY LCB-2 WATERSHED SUBAREA £§ ~ WATERSHED BOUNDARIES BASED ON F1 01-00-00 PLANS (l_ 0 n_ , 0 <D " <D ~ iL (l_ 0 PROJECT LOCATION MAP N.T.S. EXHIBIT 2 n_.__ _________ Binkley & Barfield. Inc. Consulting Engineers -----------~ ( ( ( (!) ~ C! I X w I') 0 <0 .... <0 ~ G: "' "' .., 0 0 I <0 "' I n. (.) n. ~ w (.) n. (.) n. I') 0 <0 .... <0 w ...J G: n. (.) .'fTc-• I , .. l I ·., ,' "' ...... tl .. '-"--( / -, .... ' ~-. I 1~~--~~~~~_.i~ ORT I :,sPE~CER I I ~ -,.-··-----=--=.:-_ .... 1~-·--- --~,.- r;1 __ ----·. ---· ---- LEGEND; NOTE; 8" WtJER LINE " FOReE · AIN ·, PIPELINES ENTEX WATERSHED BOUNDARIES BASED ON F1 01 -00-00 PLANS SANITARY SEWER SWBT WATERLINE UTILITY SCHEMATIC N.T.S. EXHIBIT 3 n. ...._ _________ Binkley & Barfield. Inc. Consulting Engineers -----------' ( ( ( ~ I ~ 9 c;: ~ ~ 7 ~ i1 E' ~ ....... z 0 ~ ~ w ~ I 29 ,-----.-----.-----.------.-----.-----.-----.-----.----~.-----.-----.-----.------.----~-----.-----.-----.------.-----r-----.-----.-----.------.-----r----~-----. 27 25 23 100 YR. CORRECTED EXISTING 21 19 17 15 10 YR. CORRECTED EXISTING 13 11 9 7 5 3 ~ 3: 0 <( 0 ~ m 0 ()) ()) -1 -3 -5+-----r----+---L~----+-----~--~----~----+-----~---1-----+L---~----+-----~---1-----+---L4-----~---1-----+--~4-L---+-~-1-----+----~--~ 0 740 1480 2220 2960 3700 4440 5180 5920 6660 7400 8140 8880 9620 10360 11100 11040 12580 13320 14060 14800 15540 16280 17020 17760 18500 19240 CHANNEL SECTION (X1 CARDS) WATER SURFACE PROFILES EXISTING VS CORRECTED EXISTING EXHIBIT 4 2 ~ ~------------------------------------------------------------Binkley & Barfield. Inc. Consulting Engineers -----------' ~ 29 .-----,-----,-----,-----,-----,-----,----,,----,-----;-----,-----.-----.-----.-----.-----.-----.-----.-----.-----.-----.-----.-----.-----.-----.-----,----, 27 25 23 21 19 17 1 00 YR. CORRECTED EXISTING 10 YR. UPDATED BASE 10 YR. CORRECTED EXISTING ______.. ~UPDATED BASE FLOWUNE ~ 3: I '-' I 0:: w 0 z w n.. (f) N ro 10 N f-:J_ 0 (f) 0:: w :J w 0 0:: m f-a:: (f) <( m _r: +' 3i t.D 0 I{) 0 N -<t " I{) I{) a:: a:: a.. (/) (j) 10 " t.D CORRECTED EXISTING FLOWUNE 0 (§ 0:: (/) z w (/) (j) 10 (j) ro -5+-----+-----+---~+-----+-----+-----+-----+-----~----~----+-----~----+-----+-----~-----+-----+---~~----~----r-----r----L~----r-~--r-----r-----r-~~ 0 740 1480 2220 2960 3700 4440 5180 5920 6660 7400 8140 8880 9620 10360 11100 118~0 12580 13320 14060 14800 15540 16280 17020 17760 18500 19240 CHANNEL SECTION (X1 CARDS) WATER SURFACE PROFILES CORRECTED EXISTING VS UPDATED BASE rL...-------------------------------------------------------·----Binkley & Barfield. Inc. EXHIBIT 5 Consulting Engineers __________ __. ( ( ( 29 ~ 27 I :il :;; 25 ~ 23 ~ ; 21 li! <"i 19 17 15 13 11 9 7 5 3 -1 -3 -5 ~ I I ~ .. 0 740 1480 ~ 0 (§ n::: m 0 O'l O'l 2220 2960 w w n::: 1-(/) .r:. -+-' ro .q- 0 O'l l[) 3700 4440 5180 5920 -~ ~ (}_ 1-z .o ::::E n::: ~ ·o .q-ro tD 6660 7400 ·I (/) .q- l[) N ·ro 8140 UPDATED BASE FLOWUNE ~- 3: I S2 I n::: w 0 z w (}_. (/) N ro I") N · 1 00 YR. UPDATED BASE 1-::l. 0 (/) n::: ::l o · m n::: <{ m 3 0 0 .q- l[)· UMITS OF IMPROVEMENTS ' w 0 w <{ n::: 0 1-n::: (/) n::: (/) .r:. -+-' n::: z tD (}_ w (/) (/) lO O'l O'l N I") I") " " O'l l[) (!) IX) 8880 9620 10360 11100 11640 12580 13320 14060 14800 15540 16280 17020 17760 18500 19240 CHANNEL SECTION (X1 CARDS) WATER SURFACE PROFILES UPDATED BASE VS PROPOSED UP TO SPRR EXHIBIT 6 ~ L-------------------------------------------------------------Binkley & Barfield. Inc. Consulting Engineers ------------' ( ( ( ~ ~ ~ 1l !l> ~ 16 ~ ~ 29 27 25 23 21 19 17 E' ~ - 15 z 13 0 ~ ~ 11 w 9 <0 «t 7 5 -~ I ~ (/) t:i a.. ...t w I-L() 0::: z N 1-.0 ·ro (/) :::E .c 0::: ...... ~ OCl 3 ~ 0 <( 0 ...t ·o 0 ...t (J) OCl L() <0 0::: m 0 (J) (J) -1 -3 -5 0 740 1480 2220 2960 3700 4440 5180 5920 6660 7400 8140 1 00 YR. UPDATED BASE 1 00 YR. PROPOSED 1 0 YR. UPDATED BASE UPDATED BASE FLOWLINE --~ ------- ~-1-;::). 3 u I ~ (/) w 0::: I ;::) 0 0 w <( a:: a:: 0 m I-w 0::: (/) a:: u <( z m ..c a:: (/) w ..... a:: z 0...· .. <0 a.. w (/) 3 (/) (/) N 0 L() (J) (J) OCl 0 N ,.,., ,.,., ,.,., «t r---r---(J) N · L()·L() <0 ro· LIMITS OF IMPROVEMEt-rTS 8880 9620 10360 11100 11840 12580 13320 14060 14800 15540 16280 17020 17760 18500 19240 CHANNEL SECTION {X 1 CARDS) WATER SURFACE PROFILES UPDATED BASE VS PROPOSED UP TO SENS EXHIBir 8 L------------------------------·-----------------------------Binkley & Barfield. Inc. Consulting Engineers -----------' ( ( ( ~ .. I :; ~ ~ ~ l ~ i!! ~ I ~ t; ~ 29 27 25 23 21 19 17 B 15 ~ -z 13 0 ~ ~ 11 9 7 5 3 -1 -3 -5 ~ ~ 0 <( 0 a::: Ill 0 0> 0> 0 740 1480 2220 2960 3700 5180 5920 6660 7400 814<> CD v IX) 10 YR. ULTIMATE BASE ~. ~ I (!) I a::: w u z w 0..· (/) N IX) t'1 N 100 YR. ULTIMATE BASE 1Q YR. ULTIMATE PROPOSED . . ULTIMATE PROPOSED FLOWUNE UMITS OF IMPROVEMENTS a::: a::: 0.. (/) 0> t'1 " CD 0 (§ a::: (/) z w (/) 0> t'1 0> ·ro 8880 9620 10360 11100 11840 12580 13320 14060 14800 15540 16280 17020 17760 18500 19240 CHANNEL SECTION (X1 CARDS) WATER SURFACE PROFILES ULTIMATE DEVELOPMENT CONDITIONS EXHIBIT 9 ~ '------------------------------------------------------------Binkley & Barfield. Inc. Consulting Engineers __________ __, ,.......... ~ -- TABLE 2. PHYSICAL CHARACTERISTICS FOR SUBWATERSHEDS Little Cedar Bayou Watershed Revised Existing Conditions Water- Drainage shed Length to Channel Overland Devel-Channel Area Length Centroid Slope Slope opment Improve-Convey-Pending Subwatershed (sq . mi.) (mi.) (mi.) (ft./mi.) (ft./mi.) (%) ment (%) ance (%) (%) LCB 1A 0.99 1. 60 0. 79 3 .54 10 2.9.3 2.6 30 0 LCB 1B 1.46 2..04 0.83 5.2.5 10 37 .2. 66 70 0 LCB 2. 1. 13 1. 76 0.79 2..97 10 66.2. 37 90 0 ( TABLE 3 SUBBASIN UNITGRAPH COEFFICIENTS Little Cedar Bayou Watershed Revised Existing Condit ions Subwatershed L/./s c TC+R Lca/JS D Tc R -- LCB l A 0.85 7.2.5 6.46 0.42. 2..05 0 .82. 5 .64 LCB lB 0 .89 6 .08 5 .60 0 .36 1. 59 0.54 5.06 LCB Z 1.02. 3.2.3 3 .2.8 0 .46 1. 76 0. 77 2..51 ( ( _....._ Physical Characteristics for Subwatersheds Drainage Watershed Area Length Subwatershed (sq. mi.) (mi.) LCB 1A 0.99 1.6 LCB 1B 1.46 2.04 LCB 2 1.13 1.76 Subbasin Unitgraph Coefficients Subwatershed L 1Fs Tc+R LCB 1A 0.85 14.47 LCB 1B 0.89 5.60 LCB 2 1.02 3.27 ~ Little Cedar Bayou Watershed HCFCD Unit F216-00 -00 Corrected Existing Conditions Length to Channel Overland Centroid Slope Slope Development (mi.) (ft/mi) (ft/mi) (%) 0.79 3.54 10 29.3 0.83 5.25 10 37.2 0.79 2.97 10 66.2 L ca I fs D Tc R 0.42 2.46 0.82 13.65 0.36 2.46 0.54 5.06 0.46 2.46 0.77 2.50 - Channel Improvement Conveyance Ponding Impervious (%) (%) (%) (%) 26 30 0 10 66 70 0 13 37 90 0 23 Note: These values are from the revised existing conditions for Little Cedar Bayou found in the EH&A Little Cedar Bayou Report. The values are different for LCB 1 A because the TC+R equation for DLU > 18% was used instead of the one for DLU <= 18%. L---------------------Binkley & Barfield, Inc. Consulting Engineers ---------------------' ,--. Physical Characteristics for Subwatersheds Drainage Watershed Area length Subwatershed (sq. mi.) (mi.) LCB 1A 0.86 1.34 LCB 1B 1.23 1.63 LCB 2 1 '1 0 1.73 Subbasin Unitgraph Coefficients Subwatershed L I -v's Tc+R LCB 1A 1.38 20.06 LCB 1B 0.72 3.52 LCB 2 1.17 3.60 ,-....., Little Cedar Bayou Watershed HCFCD Unit F216-00-00 Updated Base Conditions length to Channel Overland Centroid Slope Slope Development (mi.) (ft/mi) (ft/mi) (%) 0.61 0.94 1.7 30 0.74 5.1 14.8 49 0.76 2.2 9.6 66 L ea / Fs D Tc R 0.63 2.46 1.22 18.84 0.33 2.46 0.47 3.05 0.51 2.46 0.87 2.74 .---..._ Channel Improvement Conveyance Ponding Impervious (%) (%) (%) (%) 31 30 0 11 66 80 0 24 37 90 0 29 Note: The latest watershed boundaries were used (from F1 01 -00-00 plans). They were slightly different from the ultimate conditions watershed in the EH&A Little Cedar Bayou Report. L-------------------Binkley & Barfield, Inc. Consulting Engineers --------------------' - Physical Characteristics for Subwatersheds Drainage Watershed Area Length Subwatershed (sq. mi.) (mi.) LCB 1A 0.86 1.34 LCB 18 1.23 1.63 LCB2 1.10 1.73 Subbasin Unitgraph Coefficients Subwatershed Ll ~ Tc+R LCB 1A 1.38 8.87 LCB 18 0.72 2.17 LCB 2 1.17 2.72 - Little Cedar Bayou Watershed HCFCD Unit F216-00-00 Ultimate Development Conditions Length to Channel Overland Centroid Slope Slope Development (mi.) (ft/mi) (ft/mi) (%) 0.61 0.94 1.7 100 0.74 5.1 14.8 100 0.76 2.2 9.6 100 L ca / .j"; D Tc R 0.63 2.46 1.02 7.84 0.33 2.46 0.40 1.77 0.51 2.46 0.79 1.93 - Channel Improvement Conveyance Ponding Impervious (%) (%) (%) (%) 31 30 0 41 66 80 0 78 37 90 0 51 Note: The latest watershed boundaries were used (from F101-00-00 plans). They were slightly different from the ultimate conditions watershed in the EH&A Little Cedar Bayou Report. The differences between the updated base conditions and the ultimate development conditions are 1) there is 100% development assumed and 2) the percent imperviousness increased based on the City of La Porte Land Use Map. L--------------------Binkley & Barfield, Inc. Consulting Engineers ---------------------l APPENDIX B ATTACHMENT B-1 ( ( ( HEC-2 Model Comparison Existing Model vs Corrected Existing Model SECNO CWSEL Difference CWSEL TOPWID Difference TOPWID Q Difference Q Corr 1449 2328 BASE Exist Corr-Exist Corr Exist Corr-Exist Corr Exist Corr-Exist 0 3.16 -0.11 0 4.52 -0.12 0 528 3.82 -0.12 528 5.17 -0.11 0 1818 6.22 -0.12 1818 7.6 -0.11 0 1903 6.37 -0.12 >-1903 7 0 77 -0.11 <{ 0 ~ 1953 6.41 -0.13 0 1953 7.82 -0.11 <{ 0 0 1990 6.43 -0.14 a:: 1990 7.84 -0.12 co 0 f- (/) I 1- 2040 6.47 2040 7.89 2910 7.06 2910 8.67 3660 7.98 3660 9.64 4240 8.77 4240 10.57 4778 9.93 4778 11 .63 5555 11 .23 5555 12.9 5616 5616 5828 5828 5864 5864 5904 5904 5940 5940 11 .27 12.94 11.3 12.96 11.3 12.96 11.31 12.97 11 .31 12.98 -0.14 -0.12 0 -0.21 -0.21 0 -0.26 -0.29 0 -0.35 -0.36 0 -0.45 -0.41 0 -0.55 -0.4 0 -0.55 -0.4 0 -0.55 -0.39 0 -0.55 -0.38 0 -0.56 -0.39 0 -0.55 -0.39 3.05 136.75 -0.37 136.38 1520 -71 4.4 141 .19 -0.38 140.81 2410 -82 0 0 3.7 152.44 -1 .3 1 151.13 1520 -71 5.06 167.84 -1.31 166.53 2410 -82 0 0 6.1 124.66 -1.6 123.06 1520 -71 7.49 142.19 -1 .45 140.74 2410 -82 0 0 6.25 101 .95 -0.41 101.54 1370 -128 7.66 109.27 -0.66 108.61 2170 -191 0 0 6.28 102.08 -0.42 101.66 1370 -128 7.71 109.61 -0.71 108.9 2170 -191 0 0 6.29 102.12 -0.43 101.69 1370 -128 7.72 109.71 -0.72 108.99 2170 -191 6.33 7.77 6.85 8.46 7.72 9.35 8.42 10.21 9.48 11 .22 10.68 12.5 10.72 12.54 10.75 12.57 10.75 12.58 10.75 12.58 10.76 12.59 102.24 110.02 129.19 144.49 94.68 144.21 85.81 199.73 65.05 224.25 79.42 1359.67 85.04 1377.11 87.25 11 0 86.98 92 86.44 92 86.46 160 0 -0.44 -0.76 0 -1 .93 -2.01 0 -2.7 -8.66 0 -2.69 -39.85 0 -3.32 -45.06 0 -3.3 -274 0 -3.12 -280.94 0 -3.29 0 0 -3.3 0 0 -3.3 0 0 -3.31 -8.68 101.8 1370 109.26 2170 127.26 1370 142.48 2170 91.98 1370 135.55 2170 83.12 1200 159.88 1870 61.73 1200 179.19 1870 76.12 1200 1085.67 1870 81.92 1200 1096.17 1870 83.96 1080 110 1670 83.68 1080 92 1670 83.14 1080 92 1670 83.15 1080 151.32 1670 0 -1 28 -191 0 -1 28 -191 0 -128 -191 0 -173 -250 0 -173 -250 0 -1 73 -250 0 -173 -250 0 -177 -255 0 -177 -255 0 -177 -255 0 -177 -255 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. Exist represents the existing model received from HCFCD. Carr represents the corrected existing model with the corrected TC+R values. 1449 2328 1449 2328 1242 1979 1242 1979 1242 1979 1242 1979 1242 1979 1242 1979 1027 1620 1027 1620 1027 1620 1027 1620 903 1415 903 1415 903 1415 903 1415 1/4 01 /25/2000 ( ( HEC-2 Model Comparison Existing Mod el vs Corrected Existing Model r- z >- 0 <( :2 3: 0::: ~ 0::: <( <( lL a_ SECNO CWSEL Difference BASE Exist Carr-Exist 0 6151 11.33 -0.56 6151 13.01 -0.4 0 6274 11.34 -0.56 6274 13.02 -0.4 0 6696 11.41 -0.57 6696 13.1 -0.41 0 6746 11.46 -0.57 6746 13.17 -0.42 0 6840 11 .5 -0.59 6840 13.26 -0.43 0 6889 11.49 -0.59 6889 13.25 -0.44 0 6959 11.51 -0.59 6959 13.28 -0.44 7434 11 .65 7434 13.42 7494 11.66 7494 13.43 7514 11.66 7514 13.43 7534 7534 7899 7899 11.66 13.41 11 .73 13.5 0 -0.6 -0.45 0 -0.6 -0.45 0 -0.6 -0.46 0 -0.61 -0.44 0 -0.62 -0.47 CD 0::: 7947 11.77 13.56 0 -0.62 '<t lL 794 7 co I Z (f) z ...J z :2 7992 7992 8019 8019 8254 8254 12.15 14.53 12.22 14.61 12.28 14.8 -0.47 0 -0.73 -0.71 0 -0.74 -0.71 0 -0.76 -0.77 CWSEL TOPWID Carr Ex ist 10.77 88.18 12.61 320 10.78 87.94 12.62 854 10.84 78.44 12.69 459.91 10.89 99.29 12.75 509.24 10.91 99.19 12.83 560.26 10.9 78 .74 12.81 180 10.92 81.83 12.84 149.03 11.05 12.97 11.06 12.98 11 .06 12.97 11 .05 12.97 11 .11 13.03 11.15 13.09 11.42 13.82 11.48 13.9 11.52 14.03 77.44 331 .66 64 .18 329.06 58.14 318.44 54.41 311.27 53 .02 66.14 89.59 135 51 135 137 138 157.15 162 Difference Carr-Exist 0 -3.48 0 0 -3.54 -494.74 0 -3.37 -374.02 0 -2.63 -404.07 0 -2.64 -455.14 0 -3.51 -93.36 0 -3.7 -1 .3 0 -3.74 -111 .26 0 -3.03 -119.79 0 -2.69 -132.09 0 -2.49 -128.57 0 -2.59 -3.42 0 -38.59 0 0 0 0 0 0 0 0 -29 0 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. Exist represents the existing model received from HCFCD. Carr represents the corrected existing model with the corrected TC+R values. TOPWID Carr 84.7 320 84.4 359.26 75.07 85.89 96.66 105.17 96.55 105.12 75.23 86.64 78.13 147.73 a Difference Exist Carr-Exist 0 1080 -177 1670 -255 0 1080 -177 1670 -255 0 1080 -177 1670 -255 0 1080 -177 1670 -255 0 1080 -177 1670 -255 0 1080 -177 1670 -255 0 1080 -177 1670 -255 0 73.7 1080 -177 220.4 1670 61 .15 1080 209.27 1670 55.45 1080 186.35 1670 51.92 1080 182.7 1670 50.43 880 62.72 1350 51 135 51 135 137 138 128.15 162 880 1350 880 1350 880 1350 880 1350 -255 0 -177 -255 0 -177 -255 0 -177 -255 0 -117 -165 0 -117 -165 0 -1 17 -165 0 -117 -165 0 -117 -165 a Carr 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 763 1185 763 1185 763 1185 763 1185 763 1185 2/4 01:25/2000 ( ( ( HEC-2 Model Comparison Existing Model vs Corrected Existing Model SECNO CWSEL Difference CWSEL TOPWID Difference TOPWID Q Difference Q Corr I en (/) (/) 0:: >- l.U <( (.) s Z I l.U <.9 a.. (/) I BASE Exist Corr-Exist 0 8304 12.26 -0.76 8304 14.78 -0.77 0 8349 12.64 -0.88 8349 15.85 -1 .03 0 8432 12.68 -0.88 8432 15.86 -1.03 0 8712 12.83 -0.85 8712 15.93 -1 .04 0 10012 14.74 -0.86 10012 16.74 -0.88 0 11174 15.89 -0.99 11174 17.54 -0.97 0 11327 16.04 -1 11327 17.64 -0.97 0 12098 16.62 -0.77 12098 18.15 -0.82 0 12198 16.65 -0.73 12198 18.18 -0.79 0 12248 16.66 -0.72 12248 18.19 -0.78 0 12280 16.7 -0.69 12280 18.24 -0.73 0 12382 16.71 -0.69 12382 18.28 -0.75 0 12414 16.7 -0.7 12414 18.27 12464 16.76 12464 18.33 12564 16.77 12564 18.34 13864 17.47 13864 18.96 14246 17.74 -0.77 0 -0.65 -0.71 0 -0.63 -0.7 0 -0.18 -0.36 0 -0.22 Corr 11.5 14.01 11 .76 14.82 11.8 14.83 11 .98 14.89 13.88 15.86 14.9 16.57 15.04 16.67 15.85 17.33 15.92 17.39 15.94 17.41 16.01 17.51 16.02 17.53 16 17.5 16.11 17.62 16.14 17.64 17.29 18.6 17.52 Exist Corr-Exist 0 122.22 -11 .8 160 -5.71 0 78.81 -16.81 225 0 0 140.59 -20.4 225 0 0 78.24 -24.33 170 -38.72 0 80.73 -9.44 205 -112.03 0 122.71 -45.6 44 7.99 -292.57 0 78.82 -27.01 154.09 -46.63 0 66.79 -15.24 835.81 -671 .04 0 97.56 -38.52 846.86 -498.16 0 74.02 -22.98 823.04 -611 .26 0 91 .85 -44.71 826.82 -625.88 0 91 .86 -44 .69 92 -0.01 0 48.99 -5.97 429.36 79.71 427.12 72.18 458.37 39.18 107.36 366.72 -144.09 0 -8.75 -178.86 0 -15.96 -114.62 0 -0.82 -30.94 0 -250.85 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. Exist represents the existing model received from HCFCD. Corr represents the corrected existing model with the corrected TC+R values. Corr Exist Corr-Exist 0 110.42 154.29 62 225 120.19 225 53.91 131.28 71.29 92.97 77.11 155.42 51 .81 107.46 51 .55 164.77 59.04 348.7 51.04 211.78 47.14 200.94 47.17 91.99 43.02 880 -117 1350 -165 0 880 -117 1350 -165 0 880 -117 1350 -165 0 880 -117 1350 -165 0 800 -235 1220 -337 0 740 -261 11 30 -379 0 740 -261 1130 -379 0 381 39 659 1 0 381 39 659 1 0 381 39 659 1 0 381 39 659 1 0 381 39 659 1 0 372 30 285.27 643 -12 0 30 -12 70.96 372 248.26 643 56.22 372 343.75 643 38 .36 372 76.42 643 11 5.87 580 0 30 -12 0 30 -12 0 -270 763 1185 763 1185 763 1185 763 1185 565 883 479 751 479 751 420 660 420 660 420 660 420 660 420 660 402 631 402 631 402 631 402 631 310 3/4 01/25/2000 ( ( ( HEC-2 Model Comparison Existing Model vs Corrected Existing Model SECNO CWSEL Difference CWSEL TOPWID Difference BASE Exist Corr·Exist Corr Exist Corr-Exist 14246 19.23 ·0.39 18.84 650 -11.33 0 0 15321 18.33 -0.54 17.79 1422.85 -737.19 (J) 15321 19.47 -0.5 18.97 1480 0 a: 0 0 ::> 15371 18.34 -0.54 17.8 1455.93 -723.19 0 f-15371 19.47 -0.5 18.97 1510 0 co ::> 0 0 a: u 15400 18.9 -0.97 17.93 1500 -1460 <( 15400 19.49 -0.36 19.13 1500 0 co 0 0 15450 18.91 -0.96 17.95 1460 -441.87 15450 19.49 -0.35 19.14 1460 0 0 0 15635 18.93 -0.95 17.98 1200 -788.75 15635 19.51 -0.37 19.14 1200 0 f-0 0 (J) 15685 18.93 -0.95 17.98 1160 -750.74 15685 19.52 -0.37 19.15 1160 0 I 0 0 f-15725 19.1 7 -1 .07 18.1 1140 -635 <D 15725 19.71 -0.46 19.25 1140 0 0 0 15775 19.17 -1.07 18.1 1110 -606.4 15775 19.71 -0.46 19.25 1110 0 0 0 161 10 19.46 -1 .07 18.39 159.3 -84.9 16110 20.02 -0.59 19.43 349.18 -189.94 0 0 16620 19.73 -1.18 18.55 110 -69.53 16620 20.39 -0.78 19.61 110 0 0 0 16670 19.73 -1 .17 18.56 43 -2.52 a: 16670 20.41 -0.8 19.61 44 -1 a: 0 0 a.. 16739 19.83 -1 .25 18.58 43 -2.45 (J) 16739 20.44 -0.77 19.67 43 0 0 0 16789 19.83 -1 .25 18.58 140 -99.47 16789 20.46 -0.79 19.67 140 0 0 0 16821 19.84 -1 .26 18.58 200 -137.6 16821 20.47 -0.79 19.68 200 0 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. Exist represents the existing model received from HCFCO. Corr represents the corrected existing model with the corrected TC+R values. TOPWID Corr 638.67 685.66 1480 732.74 1510 40 1500 1018.13 1460 411 .25 1200 409.26 1160 505 1140 503.6 1110 74.4 159.24 40.47 110 40.48 43 40.55 43 40.53 140 62.4 200 Q Exist 880 520 800 520 800 520 800 520 800 510 770 510 770 510 770 510 770 510 770 450 680 450 680 450 680 450 680 450 680 Difference Q Corr-Exist Corr -391 489 0 -254 266 -379 421 0 -254 266 -379 421 0 -254 266 -379 421 0 -254 266 -379 421 0 -256 254 -367 403 0 -256 254 . -367 403 0 -256 254 -367 403 0 -256 254 -367 403 0 -256 254 -367 403 0 -229 221 -329 351 0 -229 221 -329 351 0 -229 221 -329 351 0 -229 221 -329 351 0 -229 221 -329 351 4/4 01 /25/2000 ( ( ( >- <x: s 0 <x: 0 0: Cl) 1- (f) I I- co HEC-2 Model Comparison Corrected Existing Model vs Updated Base Model SECNO CWSEL BASE Corr 0 3.05 0 4.4 528 3.7 528 5.06 1818 6.1 1818 7.49 1903 6.25 1903 7.66 1953 6.28 1953 7.71 1990 6.29 1990 7.72 2040 6.33 2040 7.77 2910 6.85 2910 8.46 3660 7.72 3660 9.35 4240 4240 4778 4778 5555 5555 5616 5616 5828 5828 5864 5864 5904 5904 5940 5940 8.42 10.21 9.48 11 .22 10.68 12.5 10.72 12.54 10.75 12.57 10.75 12.58 10.75 12.58 10.76 12.59 Difference CWSEL TOPWID Difference TOPWID Base-Corr Base 0.25 3.3 0.17 4.57 0 0.26 3.96 0.16 5.22 0 0.28 6.38 0.16 7.65 0 0.28 6.53 0.16 7.82 0 0.29 6.57 0.16 7.87 0 0.29 6.58 0.17 7.89 0 0.29 6.62 0.17 7.94 0 0.35 7.2 0.22 8.68 0 0.39 8.11 0.26 9.61 0 0.46 0.3 0 0.49 0.31 0 0.55 0.29 0 0.55 0.28 0 0.56 0.29 0 0.56 0.28 0 0.56 0.28 0 0.56 0.28 8.88 10.51 9.97 11.53 11.23 12.79 11.27 12.82 11.31 12.86 11 .31 12.86 11.31 12.86 11.32 12.87 Corr Base-Corr Base 136.38 0.84 137.22 140.81 0.54 141.35 0 151.13 2.95 154.08 166.53 1.86 168.39 0 123.06 3.51 126.57 140.74 2.06 142.8 0 101.54 0.92 102.46 108.61 0.99 109.6 0 101.66 0.92 102.58 108.9 1.02 109.92 0 101.69 0.93 102.62 108.99 1.02 110.01 0 101.8 0.94 102.74 109.26 1.05 110.31 0 127.26 3.25 130.51 142.48 2.07 144.55 0 91 .98 6.4 98.38 135.55 7.77 143.32 83.12 159.88 61.73 179.19 76.12 1085.67 81.92 1096.17 83.96 110 83.68 92 83.14 92 83.15 151.32 0 3.51 29.55 0 3.69 89.2 0 3.34 222 .95 0 3.15 225.79 0 3.32 966.98 0 3.33 0 0 3.33 0 0 3.34 930.24 86.63 189.43 65.42 268.39 79.46 1308.62 85 .07 1321.96 87.28 1076.98 87.01 92 86.47 92 86.49 1081 .56 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. Corr represents the corrected existing model with the corrected TC+R values. Base represents the updated base model with suN ey sections to Sens Road. Q Corr 1449 2328 1449 2328 1449 2328 1242 1979 1242 1979 1242 1979 1242 1979 1242 1979 1242 1979 1027 1620 1027 1620 1027 1620 1027 1620 903 1415 903 1415 903 1415 903 1415 Difference Q Base-Corr Base 158 1607 117 2445 0 158 1607 117 2445 0 158 1607 117 2445 0 161 1403 146 2125 0 161 1403 146 2125 0 161 1403 146 2125 0 161 1403 146 2125 0 161 1403 146 2125 0 161 1403 146 2125 0 160 170 0 160 170 0 160 170 0 160 170 0 157 177 0 157 177 0 157 177 0 157 177 1187 1790 1187 1790 1187 1790 1187 1790 1060 1592 1060 1592 1060 1592 1060 1592 115 01125i2000 ( ( ( f- z >- 0 <( 2 3;: 0::: ~ 0::: <( <( l.L 0... Q) I Z (f) z z 2 HEC-2 Model Comparison Corrected Existing Model vs Updated Base Model SECNO CWSEL Difference CWSEL TOPWID BASE Corr Base-Corr Base Corr 0 6151 10.77 0.57 11.34 84.7 6151 12.61 0.29 12.9 320 6274 6274 6696 6696 6746 6746 6840 6840 6889 6889 6959 6959 7434 7434 7494 7494 7514 7514 7534 7534 7899 7899 7947 7947 7992 7992 8019 8019 8254 8254 10.78 12.62 10.84 12.69 10.89 12.75 10.91 12.83 10.9 12.81 10.92 12.84 11.05 12.97 11.06 12.98 11.06 12.97 11.05 12.97 11 .11 13.03 11.15 13.09 11.42 13.82 11.48 13.9 11.52 14.03 0 0.57 0.29 0 0.57 0.29 0 0.57 0.3 0 0.59 0.32 0 0.59 0.32 0 0.59 0.32 0 0.59 0.33 0 0.59 0.33 0 0.59 0.33 0 0.6 0.32 0 0.59 0.33 0 0.61 0.34 0 0.74 0.61 0 0.75 0.61 0 0.78 0.67 11.35 12.91 11.41 12.98 11.46 13.05 11.5 13.15 11.49 13.13 11.51 13.16 11.64 13.3 11.65 13.31 11.65 13.3 11.65 13.29 11.7 13.36 11.76 13.43 12.16 14.43 12.23 14.51 12.3 14.7 84.4 359.26 75.07 85.89 96.66 105.17 96.55 105.12 75.23 86.64 78.13 147.73 73.7 220.4 61.15 209.27 55.45 186.35 51.92 182.7 50.43 62.72 51 135 51 135 137 138 128.15 162 Difference TOPWID Base-Corr Base 0 3.51 88.21 776.47 1096.47 0 3.56 182.89 0 3.37 303.07 0 2.63 323.1 0 2.63 376.92 0 3.5 449.16 0 3.69 328.06 0 3.7 81.55 0 2.99 87.47 0 2.66 95.59 0 2.46 92.18 0 2.49 2.4 0 39.78 169.21 0 0 442.29 0 0 160.78 0 30.66 6.11 87.96 542.15 78.44 388.96 99.29 428.27 99.18 482.04 78.73 535.8 81.82 475.79 77.4 301.95 64.14 296.74 58.11 281 .94 54.38 274.88 52.92 65.12 90.78 304.21 51 577.29 137 298.78 158.81 168.11 Notes: Each SECNO listed represents the 10-and 100-year storms. respec tively. Corr represents the corrected existing model with the corrected TC+R values. Base represents the updated base model with survey sections to Sens Road. Q Corr 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 903 1415 763 1185 763 1185 763 1185 763 11 85 763 1185 Difference Q Base-Corr Base 0 157 1060 177 1592 0 157 177 0 157 177 0 157 177 0 157 177 0 157 177 0 157 177 0 157 177 0 157 177 0 157 177 0 157 177 0 151 182 0 151 182 0 151 182 0 151 182 0 151 182 1060 1592 1060 1592 1060 1592 1060 1592 1060 1592 1060 1592 1060 1592 1060 1592 1060 1592 1060 1592 914 1367 914 1367 914 1367 914 1367 914 1367 215 01 /25t2000 ( ( HEC-2 Model Comparison Corrected Existing Model vs Updated Base Model SECNO CWSEL Difference CWSEL TOPWID Difference TOPWID Q Difference Q BASE Corr Base-Corr Base Corr Base-Corr Base Corr Base-Corr Base <D "<t ~ 8304 u. 8304 I co 8349 (/) (/) 8349 8432 8432 8712 8712 10012 10012 1117 4 11174 11 327 11327 12098 11.5 14.01 11.76 14.82 11.8 14.83 11.98 14.89 13.88 15.86 14.9 16.57 15.04 16.67 0 0 0 0.78 0.67 0 0.94 0.97 0 0.94 0.97 0 0.92 0.97 0 0.55 0.63 0 0.28 0.41 0 12.28 14.68 12.7 15.79 12.74 15.8 12.9 15.86 14.43 16.49 15.18 16.98 15.28 17.04 110.42 154.29 62 225 120.19 225 53.91 131.28 71 .29 92.97 77.11 155.42 51 .81 107.46 18.81 129.23 413.51 567.8 0 17.83 79.83 823.78 1048.78 0 22.17 142.36 827.08 1052.08 0 26.42 80.33 1172.53 1303.81 0 6.03 77.32 85.01 177.98 0 11 .55 88.66 468.95 624.37 0 1.97 53.78 18.14 125.6 0 1.2 52.75 763 1185 763 11 85 763 1185 763 1185 565 883 479 751 479 751 151 182 0 151 182 0 151 182 0 151 182 0 22 10 0 -19 -44 0 -19 -44 0 -41 914 1367 914 1367 914 1367 914 1367 587 893 460 707 460 707 ( 12098 15.85 17.33 0.24 0.37 0 0.06 0.18 0 15.91 17.51 51 .55 164.77 308.52 473.29 0 420 660 -73 0 -41 379 587 ~ >- 12198 12198 12248 12248 UJ <{ 12280 u ~ 12280 Z I UJ (9 12382 a. 12382 (f) I 12414 12414 12464 12464 12564 12564 13864 13864 14246 15.92 17.39 15.94 17.41 16.01 17.51 16.02 17.53 16 17.5 16.11 17.62 16.1 4 17.64 17.29 18.6 17.52 0.04 0.16 0 0.04 0.15 0 -0.01 0.09 0 -0.01 0.07 0 0.07 0.12 0 0.03 0.09 0 0.03 0.08 0 -0.19 -0.1 4 0 -0.23 15.96 59.04 17.55 348.7 15.98 51 .04 17.56 211 .78 16 47.14 17.6 200.94 16.01 47.17 17.6 91 .99 16.07 43.02 17.62 285.27 16.14 70.96 17.71 248.26 16.17 56.22 17.72 343.75 17.1 38.36 18.46 76.42 17.29 115.87 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. Corr represents the corrected existing model with the corrected TC+R values. Base represents the updated base model with survey sections to Sens Road. 1.08 176.87 0 1.19 153.62 0 -8.3 -108.41 0 -7.92 0.8 0 0.39 45.33 0 0.52 63.34 0 0.5 24.55 0 -0.82 -5.46 0 128.53 60.12 525.57 52.23 365.4 38.84 92.53 39.25 92.79 43.41 330.6 71.48 311 .6 56.72 368.3 37.54 70.96 244.4 420 660 420 660 420 660 420 660 402 631 402 631 402 631 402 631 310 -73 0 -41 -73 0 -41 -73 0 -41 -73 0 -47 -80 0 -47 -80 0 -47 -80 0 -47 -80 0 -68 379 587 379 587 379 587 379 587 355 551 355 551 355 551 355 551 242 3/5 01.2512000 HEC-2 Model Comparison Corrected Existing Model vs Updated Base Model ( SEC NO CWSEL Difference CWSEL TOPWID Difference TOPWID Q Difference a BASE Corr Base-Corr Base Corr Base-Corr Base Corr Base-Corr Base 14246 18.84 -0.24 18.6 638.67 2344.84 2983.51 489 -1 08 381 0 0 0 15321 17.79 -0.31 17.48 685.66 -98.95 586.71 266 -73 193 (/) 15321 18.97 -0.33 18.64 1480 1728.19 3208.19 421 -114 307 0:: 0 0 0 :::::> 15371 17.8 -0.31 17.49 732.74 -705.74 27 266 -73 193 0 1-15371 18.97 -0.33 18.64 1510 1702.01 3212.01 421 -1 14 307 co :::> 0 0 0 0:: (.) 15400 17.93 -0.4 17.53 40 -13 27 266 -73 193 <{ 15400 19.13 -0.31 18.82 1500 1881.29 3381.29 421 -114 307 co 0 0 0 15450 17.95 -0.39 17.56 1018.13 -295.71 722.42 266 -73 193 15450 19.14 -0.32 18.82 1460 1922.52 3382.52 421 -114 307 0 0 0 15635 17.98 -0.4 17.58 411.25 -169.8 241.45 254 -73 181 15635 19.14 -0.32 18.82 1200 449.06 1649.06 403 -115 288 1-0 0 0 (/) 15685 17.98 -0.39 17.59 409.26 -1 66.69 242.57 254 -73 181 15685 19.15 -0.32 18.83 1160 490.88 1650.88 403 -115 288 I 0 0 0 1-15725 18.1 -0.44 17.66 505 -243.92 261.08 254 -73 181 (!) 15725 19.25 -0.42 18.83 1140 518.65 1658.65 403 -115 288 0 0 0 ( 15775 18.1 -0.43 17.67 503.6 -243.48 260.12 254 -73 181 15775 19.25 -0.42 18.83 1110 545.92 1655.92 403 -115 288 0 0 0 16110 18.39 -0.46 17.93 74.4 -34.37 40.03 254 -73 181 16110 19.43 -0.46 18.97 159.24 172.17 331.41 403 -115 288 0 0 0 16620 18.55 -0.47 18.08 40.47 51.92 92.39 221 -74 147 16620 19.61 -0.51 19.1 110 248.93 358.93 351 -1 15 236 0 0 0 16670 18.56 -0.47 18.09 40.48 -1.2 39.28 221 -74 147 0:: 16670 19.61 -0.51 19.1 43 -1 .12 41.88 351 -115 236 0:: 0 0 0 a.. 16739 18.58 -0.46 18.12 40.55 -1.15 39.4 221 -74 147 (/) 16739 19.67 -0.46 19.21 43 -0.84 42.16 351 -1 15 236 0 0 0 16789 18.58 -0.45 18.13 40.53 65.21 105.74 221 -74 147 16789 19.67 -0.45 19.22 140 257.65 397.65 351 -115 236 0 0 0 16821 18.58 -0.45 18.13 62.4 44 .07 106.4 7 221 -74 147 16821 19.68 -0.46 19.22 200 200.54 400.54 351 -115 236 16855 NA 18.12 NA 42.07 NA 145 16855 NA 19.23 NA 2433.16 NA 232 18094 NA 18.67 NA 39.91 NA 121 ( 18094 NA 19.41 NA 2146.62 NA 194 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. Carr represents the corrected existing model with the corrected TC+R values. 4/5 Base represents the updated base model with survey sections to Sens Road. 01 /25/2000 ( ( ( HEC-2 Model Comparison Corrected Existing Model vs Updated Base Model SECNO CWSEL Difference CWSEL TOPWID Difference BASE Carr Base-Carr Base Carr Base-Carr 18874 NA 18.92 18874 NA 19.65 18934 NA 18.94 18934 NA 19.68 (/) 0 18939 NA 18.96 z <( 18939 NA 19.72 w 0 (/) a: 18939 NA 18.96 18939 NA 19.74 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. Corr represents the corrected existing model with the corrected TC+R values. Base represents the updated base model with survey sections to Sens Road. NA NA NA NA NA NA NA NA TOPWID Base 36.5 43.11 22.22 22.52 20.3 741.91 20.3 790 Q Corr Difference Q Base-Carr Base NA 106 NA 170 NA 106 NA 170 NA 106 NA 170 NA 106 NA 170 SiS 01125,2GOO ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model (with Improvements to SPRR) 1- (/) I 1- co SECNO 0 0 528 528 1818 1818 1903 1903 1953 1953 1990 1990 2040 2040 2910 2910 3660 3660 4240 4240 4778 4778 5555 5555 5616 5616 5828 5828 5864 5864 5904 5904 5940 Water Surface Elevation (ft.) BASE L:::.. PRO PRO-BASE 3.3 -0.02 3.28 4.57 -0.03 4.54 0 3.96 -0.02 3.94 5.22 -0.02 5.2 0 6.38 -0.03 6.35 7.65 -0.03 7.62 0 6.53 -0.02 6.51 7.82 -0.02 7.8 0 6.57 -0.03 6.54 7.87 -0.02 7.85 0 6.58 -0.02 6.56 7.89 -0.03 7.86 0 6.62 -0.03 6.59 7.94 -0.03 7.91 0 7.2 -0.03 7.17 8.68 -0.03 8.65 0 8.11 -0 .03 8.08 9.61 -0.03 9.58 0 8.88 -0 .04 8.84 10.51 -0.04 10.47 0 9.97 -0.04 9.93 11.53 -0.04 11.49 0 11 .23 -0.04 11.19 12.79 -0.03 12.76 0 11.27 -0.04 11.23 12.82 -0.03 12.79 0 11.31 -0.05 11.26 12.86 -0 .03 12.83 0 11.31 -0 .04 11.27 12.86 -0.03 12.83 0 11 .31 -0.04 11.27 12.86 -0.03 12.83 0 11.32 -0.05 11.27 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. BASE 137.22 141 .35 154.08 168.39 126.57 142.8 102.46 109.6 102.58 109.92 102.62 110.01 102.74 110.31 130.51 144.55 98.38 143.32 86.63 189.43 65.42 268.39 79.46 1308.62 85.07 1321.96 87.28 1076.98 87.01 92 86.47 92 86.49 BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to SPRR. Top Width (ft. b. PRO-BASE -0.08 -0.08 0 -0.26 -0.28 0 -0.3 -0.32 0 -0.08 -0.15 0 -0.08 -0.16 0 -0 .08 -0.15 0 -0.08 -0 .16 0 -0 .28 -0.3 0 -1 .15 -1.05 0 -0.31 -3 .97 0 -0 .3 -11.68 0 -0.26 -16.42 0 -0.24 -15.45 0 -0.25 -14.47 0 -0 .25 0 0 -0.26 0 0 -0.26 PRO 137.14 141.27 153.82 168.11 126.27 142.48 102.38 109.45 102.5 109.76 102.54 109.86 102.66 110.15 130.23 144.25 97.23 142.27 86.32 185.46 65.12 256.71 79.2 1292.2 84.83 1306.51 87.03 1062.51 86.76 92 86.21 92 86.23 1/5 01/20/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model f- z >- 0 <{ :2 s: 0:::: ~ 0:::: <{ <{ u.. a.. <.o 0:::: "'<1' u.. CD ::r: z (/) z z SEC NO 5940 6151 6151 6274 6274 6696 6696 6746 6746 6840 6840 6889 6889 6959 6959 7434 7434 7494 7494 7514 7514 7534 7534 7899 7899 7947 7947 7992 7992 8019 8019 8254 (with Improvements to SPRR) Water Surface Elevation (ft.) BASE L::. PRO BASE PRO-BASE 12.87 -0.03 12.84 1081 .56 0 11 .34 -0.05 11.29 88.21 12.9 -0.03 12.87 1096.47 0 11 .35 -0.05 11.3 87.96 12.91 -0.03 12.88 542.15 0 11.41 -0.04 11.37 78.44 12.98 -0.03 12.95 388.96 0 11 .46 -0.04 11.42 99.29 13.05 -0.03 13.02 428.27 0 11.5 -0.05 11.45 99.18 13.15 -0.04 13.11 482.04 0 11.49 -0.05 11.44 78.73 13.13 -0.03 13.1 535.8 0 11 .51 -0.04 11.4 7 81 .82 13.16 -0.03 13.13 475.79 0 11 .64 -0.04 11.6 77.4 13.3 -0.03 13.27 30 1.95 0 11 .65 -0.04 11.61 64.14 13.31 -0.04 13.27 296.74 0 11.65 -0.04 11.61 58.11 13.3 -0.03 13.27 28 1.94 0 11.65 -0.05 11.6 54.38 13.29 -0.03 13.26 274.88 0 11 .7 -0.04 11 .66 52.92 13.36 -0.03 13.33 65.12 0 11.76 -0.05 11.71 90.78 13.43 -0.04 13.39 304.21 0 12.16 -0.06 12.1 51 14.43 -0.07 14.36 577.29 0 12.23 -0.05 12.18 137 14.51 -0.07 14.44 298.78 0 12.3 -0.06 12.24 158.81 Notes: Each SECNO listed represents th e 10-and 100-year storms. respectively. BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to SPRR. Top Width (ft. L::. PRO-BASE -14.41 0 -0.27 -14.89 0 -0.27 -44.98 0 -0.25 -34.63 0 -0.21 -30.91 0 -0.2 -28.02 0 -0.27 -56.38 0 -0.28 -18.24 0 -0.28 -8.35 0 -0.23 -9.02 0 -0.21 -10.2 0 -0.19 -10.2 0 -0.19 -0.24 0 -2.6 -3.34 0 0 -22.39 0 0 -17.11 0 -3.06 PRO 1067.15 87.94 1081.58 87.69 497.17 78.19 354.33 99.08 397.36 98.98 454.02 78.46 479.42 81.54 457.55 77.12 293.6 63.91 287.72 57.9 271 .74 54.19 264.68 52.73 64.88 88.18 300.87 51 554.9 137 281 .67 155.75 215 01 /20/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model I a:l (j) (j) a: >- UJ <{ u ~ Z I UJ <.? 0... (J) I SECNO 8254 8304 8304 8349 8349 8432 8432 8461 8461 8712 8712 10012 10012 10900 10900 11124 11124 11174 11174 11327 11327 12098 12098 12198 12198 12248 12248 12280 12280 12382 12382 12414 (with Improvements to SPRR) Water Surface Elevation. (ft.) BASE 6. PRO BASE PRO-BASE 14.7 -0.07 14.63 168.11 0 12.28 -0.06 12.22 129.23 14.68 -0.07 14.61 567.8 0 12.7 -0.08 12.62 79.83 15.79 -0.11 15.68 1048.78 0 12.74 -0.07 12.67 142.36 15.8 -0.11 15.69 1052.08 NA 12.66 NA 15.68 12.9 -0.11 12.79 80.33 15.86 -0.11 15.75 1303.8 1 0 14.43 -1.62 12.81 77.32 16.49 -0.73 15.76 177.98 NA 12.84 NA 15.78 NA 12.85 NA 15.78 15.18 -2.36 12.82 88.66 16.98 -1 .22 15.76 624.37 0 15.28 -2.29 12.99 53.78 17.04 -1.22 15.82 125.6 0 15.91 -2.04 13.87 52.75 17.51 -1.29 16.22 473.29 0 15.96 -1.97 13.99 60.12 17.55 -1.27 16.28 525.57 0 15.98 -1.95 14.03 52.23 17.56 -1.25 16.31 365.4 0 16 -1 .98 14.02 38.84 17.6 -1 .31 16.29 92.53 0 16.01 -1.97 14.04 39.25 17.6 -1.3 16.3 92.79 0 16.07 -1.96 14.11 43.4 1 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to SPRR. Top Width (ft. /:::,. PRO-BASE -0.27 0 -1.13 -33.6 0 -1.42 -28.82 0 -2.36 -28.7 NA NA 206.46 -54.47 0 164.08 83.98 NA NA NA NA -41 .57 -507.74 0 -6.63 -49.68 0 -9.96 -413.44 0 -15.26 -452.98 0 -7.32 -295.23 0 -10.92 -42.9 0 -11.27 -42.63 0 3.6 PRO 167.84 128.1 534.2 78.41 1019.96 140 1023.38 73.1 1203.77 286.79 1249.34 241.4 261 .96 214.12 234.63 132.95 153.62 47.09 11 6.63 - 47.15 75.92 42.79 59.85 44.86 72.59 44.91 70.17 27.92 49.63 27.98 50.16 47.01 3/5 01/20/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model (/) 0::: ::> 0 I- CO ::> 0::: u <( co I- (/) I I- CD 0::: 0::: a.. (/) SECNO 12414 12464 12464 12564 12564 13864 13864 14246 14246 15321 15321 15371 15371 15400 15400 15450 15450 15635 15635 15685 15685 15725 15725 15775 15775 16110 16110 16620 16620 16670 16670 16739 16739 (with Improvements to SPRR) Water Surface Elevation (ft.) BASE D. PRO BASE PRO-BASE 17.62 -1 .24 16.38 330.6 0 16.14 -1 .98 14.16 71 .48 17.71 -1 .3 16.41 311.6 0 16.17 -1 .97 14.2 56.72 17.72 -1.29 16.43 368.3 0 17.1 -2 15.1 37.54 18.46 -1.46 17 70.96 0 17.29 -1.94 15.35 244.4 18.6 -1 .42 17.18 2983.51 0 17.48 -1 .59 15.89 586.71 18.64 -1 .14 17.5 3208.19 0 17.49 -1 .58 15.91 27 18.64 -1.15 17.49 3212.01 0 17.53 -1 .59 15.94 27 18.82 -1 .21 17.61 3381.29 0 17.56 -1 .57 15.99 722 .42 18.82 -1 .14 17.68 3382.52 0 17.58 -1 .52 16.06 241.45 18.82 -1 .1 17.72 1649.06 0 17.59 -1.52 16.07 242.57 18.83 -1 .1 17.73 1650.88 0 17.66 -1 .5 16.16 261.08 18.83 -0.98 17.85 1658.65 0 17.67 -1 .5 16.17 260.12 18.83 -0.98 17.85 1655.92 0 17.93 -1 .64 16.29 40.03 18.97 -1 .04 17.93 33 1.41 0 18.08 -1 .61 16.47 92 .39 19.1 -1.01 18.09 358.93 0 18.09 -1 .61 16.48 39 .28 19.1 -1 18.1 41.88 0 18.12 -1 .63 16.49 39.4 19.21 -1 .01 18.2 42.16 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to SPRR. Top Width (ft. D. PRO-BASE -269.99 0 -19.38 -236.64 0 -10.81 -303.46 0 9.82 -12.17 0 -203.31 -2802.14 0 -505.23 -2599.13 0 0 -3184.84 0 0 -3354.12 0 -634.88 -2252.94 0 -196.11 -1377.03 0 -202.96 -1377.17 0 -221.29 -1333.07 0 -21 0.67 -1331 .15 0 -1.58 -273.13 0 -57.23 -266.22 0 -4.07 -2.56 0 -4.19 -2.6 PRO 60.61 52.1 74.96 45.91 64.84 47.36 58.79 41 .09 181.37 81.48 609.06 27 27.17 27 27.17 87.54 11 29.58 45.34 272.03 39.61 273.71 39.79 325.58 49.45 324.77 38.45 58.28 35 .1 6 92.71 35 .21 39 .32 35 .21 39.56 4/5 01/20/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model (with Improvements to SPRR) (j) 0 z <( UJ 0 (j) a:: SEC NO 16789 16789 16821 16821 16855 16855 18094 18094 18874 18874 18934 18934 18939 18939 18963 18963 Water Surface Elevation (ft.) BASE 6. PRO PRO-BASE 0 18.13 -1 .63 16.5 19.22 -1 .01 18.21 0 18.13 -1.62 16.51 19.22 -1.01 18.21 0 18.12 -1.61 16.51 19.23 -1 .04 18.19 0 18.67 -0.72 17.95 19.41 -0.27 19.14 0 18.92 -0.52 18.4 19.65 -0.15 19.5 0 18.94 -0.5 18.44 19.68 -0.14 19.54 0 18.96 -0.5 18.46 19.72 -0.15 19.57 0 18.96 -0.49 18.47 19.74 -0.15 19.59 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. BASE 105.74 397.65 106.47 400.54 42.07 2433.16 39.91 2146.62 36.5 43.11 22.22 22.52 20.3 741 .91 20.3 790 BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to SPRR. Top Width (ft. 6. PRO-BASE 0 -70.5 -269.1 0 -71.22 -270.16 0 -17.91 -2390.12 0 -9.44 -1144.5 0 -5.27 -1.25 0 -0.2 -0.06 0 0 -197.85 0 0 -179.6 PRO 35.24 128.55 35.25 130.38 24.16 43.04 30.47 1002.12 31.23 41 .86 22.02 22.46 20.3 544.06 20.3 610.4 5/5 01/20/2000 ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model >- <( ~ 0 <( 0 0:: co SEC NO 0 0 528 528 1818 1818 1903 1903 1953 1953 1990 1990 2040 2040 2910 2910 3660 3660 4240 4240 4778 4778 5555 5555 5616 5616 5828 5828 5864 5864 5904 5904 5940 (with Improvements to Sens) Water Surface Elevation (ft.) BASE !::,. PRO BASE PRO-BASE 3.3 -0.02 3.28 137.22 4.57 -0.03 4.54 141.35 0 3.96 -0.02 3.94 154.08 5.22 -0.02 5.2 168.39 0 6.38 -0.03 6.35 126.57 7.65 -0.03 7.62 142.8 0 6.53 -0.02 6.51 102.46 7.82 -0.02 7.8 109.6 0 6.57 -0.03 6.54 102.58 7.87 -0.02 7.85 109.92 0 6.58 -0.02 6.56 102.62 7.89 -0.03 7.86 110.01 0 6.62 -0.03 6.59 102.74 7.94 -0.03 7.91 110.31 0 7.2 -0.03 7.17 130.51 8.68 -0.03 8.65 144.55 0 8.11 -0.03 8.08 98.38 9.61 -0.03 9.58 143.32 0 8.88 -0.04 8.84 86.63 10.51 -0.04 10.47 189.43 0 9.97 -0.04 9.93 65.42 11.53 -0.04 11.49 268.39 0 11.23 -0.04 11 .19 79.46 12.79 -0.03 12.76 1308.62 0 11.27 -0.04 11.23 85.07 12.82 -0.03 12.79 1321 .96 0 11 .31 -0.05 11.26 87.28 12.86 -0.03 12.83 1076.98 0 11 .31 -0.04 11.27 87.01 12.86 -0.03 12.83 92 0 11.31 -0.04 11 .27 86.47 12.86 -0.03 12.83 92 0 11.32 -0.05 11 .27 86.49 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to Sens. Top Width (ft. !::,. PRO-BASE -0.08 -0.08 0 -0.26 -0.28 0 -0.3 -0.32 0 -0.08 -0.15 0 -0.08 -0.16 0 -0.08 -0.1 5 0 -0.08 -0.16 0 -0.28 -0.3 0 -1.15 -1.05 0 -0.31 -3.97 0 -0.3 -11.68 0 -0.26 -16.42 0 -0.24 -15.45 0 -0.25 -14.47 0 -0.25 0 0 -0.26 0 0 -0.26 PRO 137.14 141 .27 153.82 168.11 126.27 142.48 102.38 109.45 102.5 109.76 102.54 109.86 102.66 110.15 130.23 144.25 97.23 142.27 86.32 185.46 65.12 256.71 79.2 1292.2 84.83 1306.51 87.03 1062.51 86.76 92 86.21 92 86.23 1/5 01/20/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model (with Improvements to Sens) 1-- z >- 0 <( ~ ~ a: ~ a: <( <( u.. a.. co I Z (/) z ....J z SECNO 5940 6151 6151 6274 6274 6696 6696 6746 6746 6840 6840 6889 6889 6959 6959 7434 7434 7494 7494 7514 7514 7534 7534 7899 7899 7947 7947 7992 7992 8019 8019 8254 Water Surface Elevation (ft.) BASE 6 PRO PRO-BASE 12.87 -0.03 12.84 0 11.34 -0.05 11 .29 12.9 -0.03 12.87 0 11.35 -0.05 11 .3 12.91 -0.03 12.88 0 11.41 -0.04 11 .37 12.98 -0.03 12.95 0 11.46 -0.04 11.42 13.05 -0.03 13.02 0 11 .5 -0.05 11.45 13.15 -0.04 13.11 0 11.49 -0.05 11.44 13.13 -0.03 13.1 0 11.51 -0.04 11.47 13.16 -0.03 13.13 0 11.64 -0.04 11 .6 13.3 -0.03 13.27 0 11.65 -0.04 11 .61 13.31 -0.04 13.27 0 11.65 -0.04 11.61 13.3 -0.03 13.27 0 11.65 -0.05 11 .6 13.29 -0.03 13.26 0 11.7 -0.04 11 .66 13.36 -0.03 13.33 0 11 .76 -0.05 11.71 13.43 -0.04 13.39 0 12.16 -0.06 12.1 14.43 -0.07 14.36 0 12.23 -0.05 12.18 14.51 -0.07 14.44 0 12.3 -0.06 12.24 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. BASE 1081 .56 88.21 1096.47 87.96 542.15 78.44 388.96 99.29 428.27 99.18 482.04 78.73 535.8 81.82 475.79 77.4 301.95 64.14 296.74 58.11 281.94 54.38 274.88 52.92 65.12 90.78 304.21 51 577.29 137 298.78 158.81 BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to Sens. Top Width (ft. 6 PRO-BASE -14.41 0 -0.27 -14.89 0 -0.27 -44.98 0 -0.25 -34.63 0 -0.21 -30.91 0 -0.2 -28.02 0 -0.27 -56.38 0 -0.28 -18.24 0 -0.28 -8.35 0 -0.23 -9.02 0 -0.21 -1 0.2 0 -0.19 -1 0.2 0 -0 .19 -0.24 0 -2.6 -3.34 0 0 -22.39 0 0 -17.1 1 0 -3.06 PRO 1067.15 87.94 1081.58 87.69 497.17 78.19 354.33 99.08 397.36 98.98 454.02 78.46 479.42 81 .54 457.55 77.12 293.6 63.91 287.72 57.9 271 .74 54.19 264.68 52.73 64.88 88.18 300.87 51 554.9 137 281.67 155.75 215 01/20/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model ..-LL I ca (/) (/) 0:: >- LU <( () ~ Z I LU (.9 a_ (J) I SECNO 8254 8304 8304 8349 8349 8432 8432 8461 8461 8712 8712 10012 10012 10900 10900 11124 11124 11174 111 74 11327 11327 12098 12098 12198 12198 12248 12248 12280 12280 12382 12382 1241 4 (with Improvements to Sens) Water Surface Elevation (ft.) BASE /::;. PRO BASE PRO-BASE 14.7 -0.07 14.63 168.11 0 12.28 -0.06 12.22 129.23 14.68 -0.07 14.61 567.8 0 12.7 -0.08 12.62 79.83 15.79 -0.11 15.68 1048.78 0 12.74 -0.07 12.67 142.36 15.8 -0.1 1 15.69 1052.08 NA 12.66 NA 15.68 12.9 -0.11 12.79 80.33 15.86 -0.11 15.75 1303.81 0 14.43 -1 .62 12.81 77.32 16.49 -0.73 15.76 177.98 NA 12.84 NA 15.78 NA 12.85 NA 15.78 15.18 -2.36 12.82 88.66 16.98 -1.22 15.76 624.37 0 15.28 -2 .29 12.99 53.78 17.04 -1.22 15.82 125.6 0 15.91 -2 .04 13.87 52.75 17.51 -1.29 16.22 473.29 0 15.96 -1 .9 7 13.99 60.12 17.55 -1.27 16.28 525.57 0 15.98 -1.95 14.03 52.23 17.56 -1 .25 16.31 365.4 0 16 -1 .98 14.02 38.84 17.6 -1 .31 16.29 92.53 0 16.01 -1 .97 14.04 39.25 17.6 -1.3 16.3 92.79 0 16.07 -1 .96 14.11 43.41 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to Sens. Top Width (ft. /::;. PRO-BASE -0.27 0 -1 .13 -33.6 0 -1 .42 -28.82 0 -2.36 -28.7 NA NA 206.46 -54.47 0 164.08 83.98 NA NA NA NA -41.57 -507.74 0 -6.63 -49.68 0 -9.96 -413.44 0 -15.26 -452.98 0 -7.32 -295.23 0 -10.92 -42.9 0 -1 1.27 -42.63 0 3.6 PRO 167.84 128.1 534.2 78.41 1019.96 140 1023.38 73.1 1203.77 286.79 1249.34 241.4 261.96 214.12 234.63 132.95 153.62 47.09 116.63 47.15 75.92 42.79 59.85 44.86 72.59 44.91 70.17 27.92 49.63 27.98 50.16 47.01 315 01/20/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model (/) a::: :::> 0 f- Cl) :::> a::: (.) <i Cl) f- (/) I f- a::: a::: a.. (/) SECNO 12414 12464 12464 12564 12564 13864 13864 14246 14246 15321 15321 15371 15371 15400 15400 15450 15450 15635 15635 15685 15685 15725 15725 15775 15775 16110 16110 16620 16620 16670 16670 16739 16739 (with Improvements to Sens) Water Surface Elevation (ft.) BASE £:::,. PRO BASE PRO-BASE 17.62 -1.24 16.38 330.6 0 16.14 -1 .98 14.16 71.48 17.71 -1 .3 16.41 311 .6 0 16.17 -1 .97 14.2 56.72 17.72 -1 .29 16.43 368.3 0 17.1 -2 15.1 37.54 18.46 -1.46 17 70.96 0 17.29 -1 .94 15.35 244.4 18.6 -1.42 17.18 2983.51 0 17.48 -1 .59 15.89 586.71 18.64 -1 .14 17.5 3208.19 0 17.49 -1 .58 15.91 27 18.64 -1 .15 17.49 3212.01 0 17.53 -1 .59 15.94 27 18.82 -1 .21 17.61 3381.29 0 17.56 -1.57 15.99 722.42 18.82 -1 .14 17.68 3382.52 0 17.58 -1.52 16.06 241.45 18.82 -1 .1 17.72 1649.06 0 17.59 -1 .52 16.07 242.57 18.83 -1 .1 17.73 1650.88 0 17.66 -1 .5 16.16 261.08 18.83 -0.98 17.85 1658.65 0 17.67 -1.5 16.17 260.12 18.83 -0.98 17.85 1655.92 0 17.93 -1 .64 16.29 40.03 18.97 -1 .04 17.93 331.41 0 18.08 -1 .61 16.47 92.39 19.1 -1 .01 18.09 358.93 0 18.09 -1 .61 16.48 39.28 19.1 -1 18.1 41.88 0 18.12 -1 .63 16.49 39.4 19.21 -1.01 18.2 42.16 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to Sens. Top Width (ft. £:::,. PRO-BASE -269.99 0 -19.38 -236.64 0 -10.81 -303.46 0 9.82 -12.17 0 -203.31 -2802.14 0 -505.23 -2599.13 0 0 -3184.84 0 0 -3354.12 0 -634.88 -2252.94 0 -196.11 -1377.03 0 -202.96 -1377.17 0 -221 .29 -1333.07 0 -210.67 -1331 .15 0 -1.58 -273.13 0 -57.23 -266.22 0 -4.07 -2.56 0 -4.19 -2.6 PRO 60.61 52.1 74.96 45.91 64.84 47.36 58.79 41 .09 181 .37 81.48 609.06 27 27.17 27 27.17 87.54 1129.58 45.34 272.03 39.61 273 .71 39.79 325.58 49.45 324.77 38.45 58.28 35.16 92.71 35.21 39.32 35.21 39.56 4/5 01/20/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Proposed Model (with Improvements to Sens) (/) 0 z < UJ 0 (/) a::: SECNO 16789 16789 16821 16821 16855 16855 18094 18094 18874 18874 18934 18934 18939 18939 18963 18963 Water Surface Elevation (ft.) BASE 1::::.. PRO PRO-BASE 0 18.13 -1 .63 16.5 19.22 -1.01 18.21 0 18.13 -1 .62 16.51 19.22 -1.01 18.21 0 18.12 -1 .62 16.5 19.23 -1 .02 18.21 0 18.67 -1.16 17.51 19.41 -0.52 18.89 0 18.92 -0.97 17.95 19.65 -0.42 19.23 0 18.94 -0.97 17.97 19.68 -0.43 19.25 0 18.96 -0.97 17.99 19.72 -0.46 19.26 0 18.96 -0.96 18 19.74 -0.46 19.28 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. BASE 105.74 397.65 106.47 400.54 42.07 2433.16 39.91 2146.62 36.5 43.11 22.22 22.52 20.3 741.91 20.3 790 BASE represents the updated base model which includes survey sections to Sens Road. PRO represents the proposed model which includes improvements up to Sens. Top Width(ft. 1::::.. PRO-BASE 0 -70.5 -269.1 0 -71 .22 -270.16 0 -1 4.13 -2358.2 1 0 -11 .07 -2101.35 0 -3.98 0.49 0 -0.39 -0.17 0 0 -620.97 0 0 -564.72 PRO 35.24 128.55 35.25 130.38 27.94 74.95 28.84 45.27 32.52 43.6 21 .83 22.35 20.3 120.94 20.3 225.28 5/5 01/20/2000 ( ( ( Water Surface Elevation Comparison Between Proposed Models INCREMENTAL CHANGE IN WATER SURFACE ELEVATION Water Surface Elevation (ft.} >- <( 3: 0 <( 0 ~ co 1- (J) I 1- co SECNO 0 0 528 528 1818 1818 1903 1903 1953 1953 1990 1990 2040 2040 2910 2910 3660 3660 4240 4240 4778 4778 5555 5555 5616 56 16 5828 5828 5864 5864 5904 5904 BASE 3.3 4.57 3.96 5.22 6.38 7.65 6.53 7.82 6.57 7.87 6.58 7.89 6.62 7.94 7.2 8.68 8.11 9.61 8.88 10.51 9.97 11.53 11 .23 12.79 11 .27 12.82 11 .31 12.86 11.31 12.86 11.31 12.86 6. NOIMP NOIMP-BASE -0.02 3.28 -0.03 4.54 0 -0.02 3.94 -0.02 5.2 0 -0.03 6.35 -0.03 7.62 0 -0.02 6.51 -0.02 7.8 0 -0.03 6.54 -0.02 7.85 0 -0.02 6.56 -0.03 7.86 0 -0.03 6.59 -0.03 7.91 0 -0.03 7.17 -0.03 8.65 0 -0.03 8.08 -0.03 9.58 0 -0.04 8.84 -0.04 10.47 0 -0.04 9.93 -0.04 11.49 0 -0.04 11 .19 -0.03 12.76 0 -0.04 11.23 -0.03 12.79 0 -0.05 11 .26 -0.03 12.83 0 -0.04 11.27 -0.03 12.83 0 -0.04 11 .27 -0.03 12.83 0 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. NOIMP represents no improvements upstream of SPRR. IMPR represents flow line lowering upstream of SPRR to Sens Road. 6. IMPR·NOIMP 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 IMPR 3.28 4.54 3.94 5.2 6.35 7.62 6.51 7.8 6.54 7.85 6.56 7.86 6.59 7.91 7.17 8.65 8.08 9.58 8.84 10.47 9.93 11.49 11 .19 12.76 11.23 12.79 11.26 12.83 11 .27 12.83 11.27 12.83 1/5 01/21/2000 ( ( ( Water Surface Elevation Comparison Between Proposed Models INCREMENTAL CHANGE IN WATER SURFACE ELEVATION Water Surface Elevation (ft.) co I Z (/) z SECNO 5940 5940 6151 6151 6274 6274 6696 6696 6746 6746 6840 6840 6889 6889 6959 6959 7434 7434 7494 7494 7514 7514 7534 7534 7899 7899 7947 7947 7992 7992 8019 8019 BASE 11.32 12.87 11.34 12.9 11.35 12.91 11.41 12.98 11.46 13.05 11 .5 13.15 11.49 13.13 11.51 13.16 11.64 13.3 11.65 13.31 11.65 13.3 11 .65 13.29 11.7 13.36 11 .76 13.43 12.16 14.43 12.23 14.51 C::. NOIMP NOIMP·BASE -0.05 11.27 -0.03 12.84 0 -0.05 11.29 -0.03 12.87 0 -0.05 11.3 -0.03 12.88 0 -0.04 11.37 -0.03 12.95 0 -0.04 11.42 -0.03 13.02 0 -0.05 11.45 -0.04 13.11 0 -0.05 11.44 -0.03 13.1 0 -0.04 11.47 -0.03 13.13 0 -0.04 11.6 -0.03 13.27 0 -0.04 11.61 -0.04 13.27 0 -0.04 11.61 -0.03 13.27 0 -0.05 11.6 -0.03 13.26 0 -0.04 11.66 -0.03 13.33 0 -0.05 11.71 -0.04 13.39 0 -0.06 12.1 -0.07 14.36 0 -0.05 12.18 -0.07 14.44 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. NOIMP represents no improvements upstream of SPRR. IMPR represents now line lowering upstream of SPRR to Sens Road. C::. IMPR·NOIMP 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 IMPR 11.27 12.84 11.29 12.87 11.3 12.88 11.37 12.95 11.42 13.02 11 .45 13.11 11.44 13.1 11.4 7 13.1 3 11.6 13.27 11.61 13.27 11.61 13.27 11.6 13.26 11 .66 13.33 11 .71 13.39 12.1 14.36 12.18 14.44 2/5 01/21/2000 ( ( ( Water Surface Elevation Comparison Between Proposed Models INCREMENTAL CHANGE IN WATER SURFACE ELEVATION Water Surface Elevation {ft.) z 2 I CO (/) (/) SECNO 8254 8254 8304 8304 8349 8349 8432 8432 8461 8461 8712 8712 10012 10012 10900 10900 11124 11124 111 74 11174 11327 11327 12098 12098 12198 12198 12248 12248 BASE 12.3 14.7 12.28 14.68 12.7 15.79 12.74 15.8 12.9 15.86 14.43 16.49 15.18 16.98 15.28 17.04 15.91 17.51 15.96 17.55 15.98 17.56 6. NOIMP NOIMP·BASE 0 ·0.06 12.24 -0.07 14.63 0 -0.06 12.22 -0.07 14.61 0 -0.08 12.62 -0.11 15.68 0 -0.07 12.67 -0.11 15.69 NA 12.66 NA 15.68 -0.11 12.79 -0.11 15.75 0 -1.62 12.81 -0.73 15.76 NA 12.84 NA 15.78 NA 12.85 NA 15.78 -2.36 12.82 -1.22 15.76 0 -2.29 12.99 -1.22 15.82 0 -2.04 13.87 -1.29 16.22 0 -1 .97 13.99 -1 .27 16.28 0 -1 .95 14.03 -1 .25 16.31 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. NOIMP represents no improvements upstream of SPRR. IMPR represents now line lowering upstream of SPRR to Sens Road. 6.. IMPR·NOIMP 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 IMPR 12.24 14.63 12.22 14.61 12.62 15.68 12.67 15.69 12.66 15.68 12.79 15.75 12.81 15.76 12.84 15.78 12.85 15.78 12.82 15.76 12.99 15.82 13.87 16.22 13.99 16.28 14.03 16.31 3/5 01i21 2000 ( ( ( Water Surface Elevation Comparison Between Proposed Models INCREMENTAL CHANGE IN WATER SURFACE ELEVATION Water Surface Elevation (ft.) a:: >- L.U <( u ~ Z I L.U <.9 a.. (f) I (/) a:: :::> 0 I- OJ :::> a:: u <( OJ I- (/) I 1-- <.D SECNO 12280 12280 12382 12382 12414 12414 12464 12464 12564 12564 13864 13864 14246 14246 15321 15321 15371 15371 15400 15400 15450 15450 15635 15635 15685 15685 15725 15725 15775 15775 16110 16110 BASE 16 17.6 16.01 17.6 16.07 17.62 16.14 17.71 16.17 17.72 17.1 18.46 17.29 18.6 17.48 18.64 17.49 18.64 17.53 18.82 17.56 18.82 17.58 18.82 17.59 18.83 17.66 18.83 17.67 18.83 17.93 18.97 !::::. NOIMP NOIMP-BASE 0 -1.98 14.02 -1 .31 16.29 0 -1.97 14.04 -1 .3 16.3 0 -1 .96 14.11 -1 .24 16.38 0 -1 .98 14.16 -1.3 16.41 0 -1 .97 14.2 -1.29 16.43 0 -2 15.1 -1.46 17 0 -1.94 15.35 -1.42 17.18 0 -1 .59 15.89 -1 .14 17.5 0 -1 .58 15.91 -1.15 17.49 0 -1 .59 15.94 -1 .21 17.61 0 -1.57 15.99 -1 .14 17.68 0 -1 .52 16.06 -1 .1 17.72 0 -1 .52 16.07 -1 .1 17.73 0 -1 .5 16.16 -0.98 17.85 0 -1.5 16.17 -0.98 17.85 0 -1 .64 16.29 -1.04 17.93 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. NOIMP represents no improvements upstream of SPRR. IMPR represents now line lowering upstream of SPRR to Sens Road. !::::. IMPR-N OIMP 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 IMPR 14.02 16.29 14.04 16.3 14.11 16.38 14.16 16.41 14.2 16.43 15.1 17 15.35 17.18 15.89 17.5 15.91 17.49 15.94 17.61 15.99 17.68 16.06 17.72 16.07 17.73 16.16 17.85 16.17 17.85 16.29 17.93 4/5 01/21/2000 ( ( ( Water Surface Elevation Comparison Between Proposed Models INCREMENTAL CHANGE IN WATER SURFACE ELEVATION Water Surface Elevation (ft} 0::: 0::: a... (/) (/) 0 z <( UJ 0 (/)· 0::: SECNO 16620 16620 16670 16670 16739 16739 16789 16789 16821 16821 16855 16855 18094 18094 18874 18874 18934 18934 18939 18939 18963 18963 BASE 18.08 19.1 18.09 19.1 18.12 19.21 18.13 19.22 18.13 19.22 18.12 19.23 18.67 19.41 18.92 19.65 18.94 19.68 18.96 19.72 18.96 19.74 D. NOIMP NOIMP-BASE 0 -1.61 16.47 -1 .01 18.09 0 -1.61 16.48 -1 18.1 0 -1 .63 16.49 -1.01 18.2 0 -1.63 16.5 -1.01 18.21 0 -1 .62 16.51 -1 .01 18.21 0 -1.61 16.51 -1 .04 18.19 0 -0.72 17.95 -0.27 19.14 0 -0.52 18.4 -0.15 19.5 0 -0.5 18.44 -0.14 19.54 0 -0.5 18.46 -0.15 19.57 0 -0.49 18.47 -0.15 19.59 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. NOIMP represents no improvements upstream of SPRR. IMPR represents flow line lowering upstream of SPRR to Sens Road. 6. IMPR-NOIMP 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -0.01 0.02 0 -0.44 -0.25 0 -0.45 -0.27 0 -0.47 -0.29 0 -0.47 -0.31 0 -0.47 -0.31 IMPR 16.47 18.09 16.48 18.1 16.49 18.2 16.5 18.21 16.51 18.21 16.5 18.21 17.51 18.89 17.95 19.23 17.97 19.25 17.99 19.26 18 19.28 SiS 01121/2000 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Ultimate Base Model >- <( !== 0 <( 0 0:: Cl) f- (j) I f- co SECNO 0 0 528 528 1818 1818 1903 1903 1953 1953 1990 1990 2040 2040 2910 2910 3660 3660 4240 4240 4778 4778 5555 5555 5616 5616 5828 5828 5864 5864 5904 5904 5940 Water Surface Elevation (ft.) BASE /;:. ULT ULT-BASE 3.3 0.95 4.25 4.57 0.74 5.31 0 3.96 0.95 4.91 5.22 0.74 5.96 0 6.38 0.95 7.33 7.65 0.73 8.38 0 6.53 0.97 7.5 7.82 0.73 8.55 0 6.57 0.98 7.55 7.87 0.74 8.61 0 6.58 0.99 7.57 7.89 0.82 8.71 0 6.62 1 7.62 7.94 0.83 8.77 0 7.2 1.15 8.35 8.68 0.95 9.63 0 8.11 1.17 9.28 9.61 1.04 10.65 0 8.88 1.32 10.2 10.51 1.06 11.57 0 9.97 1.33 11.3 11 .53 1.01 12.54 0 11.23 1.4 12.63 12.79 0.82 13.61 0 11.27 1.41 12.68 12.82 0.8 13.62 0 11 .31 1.4 12.71 12.86 0.79 13.65 0 11 .31 1.4 12.71 12.86 0.77 13.63 0 11 .31 1.41 12.72 12.86 0.83 13.69 0 11.32 1.4 12.72 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. BASE represents the updated base model which includes survey data up to Sens Road. UL T represents the ultimate base model which assumes 100% development. Top Width (ft. BASE t::. ULT-BASE 137.22 3.09 141.35 2.43 0 154.08 10.71 168.39 8.5 0 126.57 12.23 142.8 9.28 0 102.46 5.17 109.6 4.16 0 102.58 5.36 109.92 3.84 0 102.62 5.41 110.01 3.75 0 102.74 5.58 110.3 1 3.45 0 130.51 10.9 144.55 9.04 0 98.38 34.92 143.32 143.72 0 86.63 73.73 189.43 162.12 0 65.42 146.68 268.39 312.9 0 79.46 1076.82 1308.62 860.22 0 85.07 1138.7 1321 .96 857.36 0 87.28 903.67 1076.98 1208.72 0 87.01 4.99 92 0 0 86.47 5.53 92 0 0 86.49 911 .81 ULT 140.31 143.78 164.79 176.89 138.8 152.08 107.63 113.76 107.94 113.76 108.03 113.76 108.32 113.76 141.41 153.59 133.3 287.04 160.36 351 .55 212.1 581.29 1156.28 2168.84 1223.77 2179.32 990.95 2285.7 92 92 92 92 998.3 1/5 ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Ultimate Base Model f- z >- 0 <( :2 ~ a:: ~ a:: <( <( LL Cl.. <D a:: '<!" LL co I Z (/) z z SECNO 5940 6151 6151 6274 6274 6696 6696 6746 6746 6840 6840 6889 6889 6959 6959 7434 7434 7494 7494 7514 7514 7534 7534 7899 7899 7947 7947 7992 7992 8019 8019 8254 Water Surface Elevation (ft.) BASE L::::. ULT ULT-BASE 12.87 0.89 13.76 0 11.34 1.41 12.75 12.9 0.88 13.78 0 11.35 1.41 12.76 12.91 0.88 13.79 0 11.41 1.43 12.84 12.98 0.88 13.86 0 11.46 1.45 12.91 13.05 0.89 13.94 0 11.5 1.51 13.01 13.15 0.79 13.94 0 11.49 1.5 12.99 13.13 0.8 13.93 0 11.51 1.51 13.02 13.16 0.8 13.96 0 11.64 1.53 13.17 13.3 0.82 14.12 0 11.65 1.52 13.17 13.31 0.81 14.12 0 11.65 1.52 13.17 13.3 0.82 14.12 0 11.65 1.51 13.16 13.29 0.79 14.08 0 11.7 1.52 13.22 13.36 0.77 14.13 0 11.76 1.53 13.29 13.43 0.84 14.27 0 12.16 2.14 14.3 14.43 1.61 16.04 0 12.23 2.16 14.39 14.51 1.62 16.13 0 12.3 2.28 14.58 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. BASE represents the updated base model which includes survey data up to Sens Road. UL T represents the ultimate base model which assumes 100% development. Top Width (ft. BASE L::::. ULT-BASE 1081.56 1420.56 0 88.21 929.5 1096.47 1465.31 0 87.96 347.18 542.15 2328.8 0 78.44 155.58 388.96 850.92 0 99.29 6.62 428.27 869.12 0 99.18 263.14 482.04 817.76 0 78.73 328.59 535.8 757.23 0 81 .82 316.39 475.79 820.05 0 77.4 191.16 301.95 698.09 0 64.14 196.92 296.74 706.69 0 58.11 183.41 281.94 720.65 0 54 .38 179.74 274.88 720.32 0 52.92 11.19 65.12 6.85 0 90.78 200.17 304.21 217.61 0 51 483.84 577.29 1958.92 0 137 132.49 298.78 2378.33 0 158.81 8.86 ULT 2502.12 1017.71 2561.78 435.14 2870.95 234.02 1239.88 105.91 1297.39 362.32 1299.8 407.32 1293.03 398.21 1295.84 268.56 1000.04 261 .06 1003.43 241.52 1002.59 234.12 995.2 64.1 1 71.97 290.95 521 .82 534.84 2536.21 269.49 2677.11 167.67 215 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Ultimate Base Model <D '<!" 0:: LL I en (f) (f) 0:: >- UJ <( u s Z I UJ <..? (L (f) I SECNO 8254 8304 8304 8349 8349 8432 8432 8712 8712 10012 10012 11174 11174 11327 11327 12098 12098 12198 12198 12248 12248 12280 12280 12382 12382 12414 12414 12464 12464 12564 12564 13864 Water Suriace Elevation (ft.) BASE L::::.. ULT ULT-BASE 14.7 1.85 16.55 0 12.28 2.28 14.56 14.68 1.87 16.55 0 12.7 2.99 15.69 15.79 1.92 17.71 0 12.74 2.96 15.7 15.8 1.91 17.71 12.9 2.87 15.77 15.86 1.88 17.74 0 14.43 2.05 16.48 16.49 1.48 17.97 15.18 1.89 17.07 16.98 1.29 18.27 0 15.28 1.86 17.14 17.04 1.25 18.29 0 15.91 1.77 17.68 17.51 1.26 18.77 0 15.96 1.77 17.73 17.55 1.25 18.8 0 15.98 1.77 17.75 17.56 1.25 18.81 0 16 1.79 17.79 17.6 1.26 18.86 0 16.01 1.79 17.8 17.6 1.4 19 0 16.07 1.75 17.82 17.62 1.36 18.98 0 16.14 1.77 17.91 17.71 1.33 19.04 0 16.17 1.76 17.93 17.72 1.34 19.06 0 17.1 1.65 18.75 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. BASE represents the updated base model which includes survey data up to Sens Road. UL T represents the ultimate base model which assumes 100% development. Top Width (ft. BASE L::::.. ULT-BASE 168.11 229.12 0 129.23 385.97 567.8 692.02 0 79.83 942.57 1048.78 326.22 0 142.36 883.69 1052.08 322.92 80.33 1173.34 1303.81 1811 .95 0 77.32 99.95 177.98 2258.46 88.66 701 .91 624.37 2791.41 0 53.78 76.43 125.6 258.28 0 52.75 540.3 473.29 541 .64 0 60.12 575.18 525.57 519.37 0 52.23 437.7 365.4 791.51 0 38.84 56.48 92.53 1127.69 0 39.25 56.21 92.79 1200.17 0 43.41 329.53 330.6 684.36 0 71.48 297.33 311.6 747.28 0 56.72 336.76 368.3 788.91 0 37.54 44.78 ULT 397.23 515 .2 1259.82 1022.4 1375 1026.05 1375 1253.67 3115.76 177.27 2436.44 790.57 3415.78 130.21 383.88 593.05 1014.93 635.3 1044.94 489.93 1156.91 95.32 1220.22 95.46 1292.96 372 .94 1014.96 368.81 1058.88 393.48 1157.21 82.32 3/5 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Ultimate Base Model (/) n:: => 0 I- CO => n:: (.) <( co 1- (/) I 1- <0 n:: n:: a.. (/) SECNO 13864 14246 14246 15321 15321 15371 15371 15400 15400 15450 15450 15635 15635 15685 15685 15725 15725 15775 15775 16110 16110 16620 16620 16670 16670 16739 16739 16789 16789 16821 16821 16855 16855 Water Surface Elevation (ft.) BASE 6 ULT ULT-BASE 18.46 1.29 19.75 0 17.29 1.63 18.92 18.6 1.34 19.94 0 17.48 1.47 18.95 18.64 1.32 19.96 0 17.49 1.46 18.95 18.64 1.32 19.96 0 17.53 1.54 19.07 18.82 1.14 19.96 0 17.56 1.51 19.07 18.82 1.14 19.96 0 17.58 1.49 19.07 18.82 1.14 19.96 0 17.59 1.49 19.08 18.83 1.13 19.96 0 17.66 1.42 19.08 18.83 1.14 19.97 0 17.67 1.41 19.08 18.83 1.14 19.97 0 17.93 1.3 19.23 18.97 1.07 20 .04 0 18.08 1.31 19.39 19.1 1.06 20 .16 0 18.09 1.3 19.39 19.1 1.05 20.15 0 18.12 1.46 19.58 19.21 1.35 20.56 0 18.13 1.47 19.6 19.22 1.39 20.61 0 18.1 3 1.47 19.6 19.22 1.39 20.61 0 18.12 1.5 19.62 19.23 1.39 20 .62 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. BASE represents the updated base model which includes survey data up to Sens Road. UL T represents the ultima te base model which assumes 100% development. Top Width (ft. BASE 6 ULT-BASE 70.96 402.78 0 244.4 2937.93 2983.51 709.36 0 586.71 2931 .16 3208.19 1204.94 0 27 3493.8 3212.01 1201 .96 0 27 3598.93 3381.29 1033.62 0 722.42 2904.38 3382.52 1032.7 0 241.45 1760.5 1649.06 1206 0 242.57 1761 .96 1650.88 1205.07 0 261.08 1752.72 1658.65 1201.4 0 260.12 1750.85 1655.92 1203.93 0 40.03 377.95 331.41 557.05 0 92.39 435.48 358.93 679.21 0 39.28 3.33 41 .88 1.12 0 39.4 3.58 42.16 0.84 0 105.74 529.96 397.65 1468.02 0 106.47 537.11 400.54 1491.36 0 42.07 3285.97 2433.16 1812.84 ULT 473.74 3182.33 3692.87 3517.87 4413.13 3520.8 4413.97 3625.93 4414.91 3626.8 4415.22 2001 .95 2855 .06 2004.53 2855.95 2013.8 2860.05 2010.97 2859.85 417.98 888.46 527.87 1038.14 42.61 43 42.98 43 635.7 1865.67 643.58 1891 .9 3328.04 4246 415 ( ( ( Water Surface Elevation and Top Width Comparison Updated Base Model vs Ultimate Base Model (/) 0 z <{ UJ 0 (/) ~ SECNO 18094 18094 18874 18874 18934 18934 18939 18939 18963 18963 Water Surface Elevation (ft.) BASE !::. ULT ULT-BASE 0 18.67 1.05 19.72 19.41 1.22 20.63 0 18.92 1.05 19.97 19.65 1.21 20.86 0 18.94 1.07 20.01 19.68 1.22 20.9 0 18.96 1.13 20.09 19.72 1.33 21 .05 0 18.96 1.14 20.1 19.74 1.31 21.05 Notes: Each SECNO listed represents the 10-and 100-year storms. respectively. BASE represents the updated base model which includes survey data up to Sens Road. UL T represents the ultimate base model which assumes 100% development. Top Width (ft. BASE !::. ULT-BASE 0 39.91 3354.14 2146.62 2395.38 0 36.5 16.45 43.11 17.89 0 22.22 0.44 22.52 3.65 0 20.3 1099.7 741.91 378.09 0 20.3 1099.7 790 330 ULT 3394.05 4542 52.95 61 22.66 26.17 1120 1120 1120 1120 5/5 ( ( ( Water Surface Elevation and Top Width Comparison Ultimate Base Model vs Ultimate Proposed Model 1-- (J) I I- co SECNO 0 0 528 528 1818 1818 1903 1903 1953 1953 1990 1990 2040 2040 2910 2910 3660 3660 4240 4240 4778 4778 5555 5555 5616 5616 5828 5828 5864 5864 5904 5904 5940 Water Surface Elevation ( ft.) ULT BASE 6 ULT PRO ULT PRO-ULT BASE 4.25 -0 .04 4.21 5.31 -0 .01 5.3 0 4.91 -0 .04 4.87 5.96 -0 .01 5.95 0 7.33 -0 .03 7.3 8.38 -0.01 8.37 0 7.5 -0 .04 7.46 8.55 -0 .01 8.54 0 7.55 -0 .04 7.51 8.61 -0 .0 1 8.6 0 7.57 -0 .04 7.53 8.71 -0.01 8.7 0 7.62 -0.04 7.58 8.77 -0 .02 8.75 0 8.35 -0 .05 8.3 9.63 -0.02 9.61 0 9.28 -0 .05 9.23 10.65 -0.02 10.63 0 10.2 -0.05 10.15 11.57 -0 .02 11.55 0 11.3 -0.05 11.25 12.54 -0.02 12.52 0 12.63 -0.04 12.59 13.61 -0.02 13.59 0 12.68 -0.05 12.63 13.62 -0.01 13.61 0 12.71 -0.04 12.67 13.65 -0.02 13.63 0 12.71 -0.04 12.67 13.63 -0.02 13.61 0 12.72 -0.04 12.68 13.69 -0.01 13.68 0 12.72 -0.04 12.68 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. UL T BASE represents the ultimate development base model. UL T PRO represents the ultimate development proposed model. Top Width (ft.) ULT BASE 1::::. UL T PRO-UL T BASE 140.31 -0.11 143.78 -0.05 0 164.79 -0.41 176.89 -0.14 0 138.8 -0.46 152.08 -0.16 0 107.63 -0.23 113.76 0 0 107.94 -0.23 113.76 0 0 108.03 -0.23 113.76 0 0 108.32 -0.23 113.76 0 0 141.41 -0.41 153.59 -0.17 0 133.3 -1.46 287.04 -3.97 0 160.36 -4.88 351 .55 -2.84 0 212.1 -7.98 581.29 -6.54 0 1156.28 -54.96 2168.84 -9.35 0 1223.77 -62.5 2179.32 -9.75 0 990.95 -26.25 2285.7 -32.56 0 92 0 92 0 0 92 0 92 0 0 998.3 -26.15 ULT PRO 140.2 143.73 164.38 176.75 138.34 151.92 107.4 113.76 107.71 113.76 107.8 113.76 108.09 113.76 141 153.42 131 .84 283.07 155.48 348.71 204.12 574.75 1101 .32 2159.49 1161.27 2169.57 964.7 2253.14 92 92 92 92 972.15 1/5 ( ( ( Water Surface Elevation and Top Width Comparison Ultimate Base Model vs Ultimate Proposed Model 1-- z >- 0 <( 2 3: 0:: ~ -0:: <( <( u.. a.. c.o 0:: "<:t u.. ell I Z (/) z z SEC NO 5940 6151 6151 6274 6274 6696 6696 6746 6746 6840 6840 6889 6889 6959 6959 7434 7434 7494 7494 7514 7514 7534 7534 7899 7899 7947 7947 7992 7992 8019 8019 8254 Water Surface Elevation ( ft.) ULT BASE 6 ULT PRO UL T PRO-UL T BASE 13.76 -0.02 13.74 0 12.75 -0.04 12.71 13.78 -0.02 13.76 0 12.76 -0.04 12.72 13.79 -0.02 13.77 0 12.84 -0.04 12.8 13.86 -0.02 13.84 0 12.91 -0.04 12.87 13.94 -0.02 13.92 0 13.01 -0.05 12.96 13.94 -0.02 13.92 0 12.99 -0.04 12.95 13.93 -0.02 13.91 0 13.02 -0.04 12.98 13.96 -0.02 13.94 0 13.17 -0.05 13.12 14.12 -0.03 14.09 0 13.17 -0.04 13.13 14.12 -0.02 14.1 0 13.17 -0.05 13.12 14.12 -0.02 14.1 0 13.16 -0.05 13.11 14.08 -0.01 14.07 0 13.22 -0.05 13.17 14.13 -0.01 14.12 0 13.29 -0.05 13.24 14.27 -0 .02 14.25 0 14.3 -0 .07 14.23 16.04 -0 .03 16.01 0 14.39 -0 .08 14.31 16.13 -0.03 16.1 0 14.58 -0.08 14.5 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. UL T BASE represents the ultimate development base model. UL T PRO represents the ultimate development proposed model. To_2_ Width (ft.) ULT BASE 6 ULT PRO-ULT BASE 2502.12 -39.65 0 1017.71 -26.79 2561.78 -40.09 0 435.14 -21.96 2870.95 -16.5 0 234.02 -44.44 1239.88 -1 5.49 0 105.91 -0.19 1297.39 -15.41 0 362.32 -256.6 1299.8 -14.93 0 407.32 -47.27 1293.03 -15.38 0 398.21 -24 .58 1295.84 -15.3 0 268.56 -11 .22 1000.04 -3.65 0 261.06 -11.98 1003.43 -3.66 0 241.52 -13.55 1002.59 -3.67 0 234.12 -13.59 995.2 -3.5 0 64.11 -0.32 71.97 -0.3 0 290.95 -4.42 521.82 -6.98 0 534.84 -27.04 2536.21 -9.77 0 269.49 -9.45 2677.11 -4.68 0 167.67 -0.32 ULT PRO 2462.47 990.92 2521 .69 413.18 2854.45 189.58 1224.39 105.72 1281.98 105.72 1284.87 360.05 1277.65 373.63 1280.54 257.34 996.39 249.08 999.77 227.97 998.92 220.53 991 .7 63.79 71.67 286.53 514.84 507.8 2526.44 260.04 2672.43 167 .35 215 ( ( ( Water Surface Elevation and Top Width Comparison Ultimate Base Model vs Ultimate Proposed Model I CO (/) (/) a::: >- w <( (.) 5: Z I w 0 a.. (J) I SECNO 8254 8304 8304 8349 8349 8432 8432 8461 8461 8712 8712 10012 10012 10900 10900 11124 11124 11 174 11174 11327 11327 12098 12098 12198 12198 12248 12248 12280 12280 12382 12382 12414 Water Surface Elevation (ft.) ULT BASE 6 ULT PRO ULT PRO-ULT BASE 16.55 -0 .04 16.51 0 14.56 -0.08 14.48 16.55 -0.04 16.51 0 15.69 -0.12 15.57 17.71 -0.04 17.67 0 15.7 -0.12 15.58 17.71 -0.03 17.68 NA 15.57 NA 17.68 15.77 -0.12 15.65 17.74 -0.04 17.7 0 16.48 -0.82 15.66 17.97 -0.26 17.71 NA 15.68 NA 17.72 NA 15.68 NA 17.73 17.07 -1.42 15.65 18.27 -0.56 17.71 0 17.14 -1 .4 15.74 18.29 -0.55 17.74 0 17.68 -1.42 16.26 18.77 -0.65 18.12 0 17.73 -1.39 16.34 18.8 -0.63 18.17 0 17.75 -1.38 16.37 18.81 -0.62 18.19 0 17.79 -1.44 16.35 18.86 -0.68 18.18 0 17.8 -1.43 16.37 19 -0.81 18.19 0 17.82 -1.35 16.47 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. UL T BASE represents the ultimate development base model. UL T PRO represents the ultimate development proposed model. Top Width (ft.) ULT BASE 6 Ul T PRO-Ul T BASE 397.23 -2.73 0 515.2 -36.09 1259.82 -1 2.11 0 1022.4 -163.77 1375 0 0 1026.05 -162.88 1375 0 NA NA 1253.67 -60.3 3115.76 -1 9.04 0 177.27 83.97 2436.44 -848.6 NA NA NA NA 790.57 -678.59 3415.78 -1 353.73 0 130.21 -57.99 383.88 -225.25 0 593.05 -532.47 1014.93 -187.55 0 635.3 -561.23 1044.94 -203.24 0 489.93 -418.49 1156.91 -336.94 0 95.32 -43.57 1220.22 -1121 .92 0 95.46 -42.99 1292.96 -11 94.66 0 372.94 -311.81 ULT PRO 394.5 479.11 1247.71 858.63 1375 863.17 1375 872.75 3082.61 1193.37 3096.72 261.24 1587.84 233.92 2060.51 152.92 2584.07 111 .98 2062.05 72.22 158.63 60.58 827.38 74.07 841 .7 71.44 819.97 51.75 98.3 52.47 98.3 61.13 3/5 ( ( ( Water Surface Elevation and Top Width Comparison Ultimate Base Model vs Ultimate Proposed Model (j) a:: ::J 0 I- CO ::> a:: 0 <( co 1- (j) I I- a:: a:: Cl. (j) SECNO 12414 12464 12464 12564 12564 13864 13864 14246 14246 15321 15321 15371 15371 15400 15400 15450 15450 15635 15635 15685 15685 15725 15725 15775 15775 16110 1611 0 16620 16620 16670 16670 16739 16739 Water Surface Elevation (ft.) ULT BASE 6 ULT PRO ULT PRO-ULT BASE 18.98 -0.73 18.25 0 17.91 -1.4 16.51 19.04 -0.76 18.28 0 17.93 -1.39 16.54 19.06 -0.76 18.3 0 18.75 -1.51 17.24 19.75 -0.89 18.86 0 18.92 -1.47 17.45 19.94 -0.95 18.99 0 18.95 -1 .14 17.81 19.96 -0.92 19.04 0 18.95 -1.15 17.8 19.96 -0.92 19.04 0 19.07 -1 .07 18 19.96 -0.77 19.19 0 19.07 -0.95 18.12 19.96 -0.77 19.19 0 19.07 -0.92 18.15 19.96 -0.76 19.2 0 19.08 -0.92 18.16 19.96 -0.76 19.2 0 19.08 -0.9 18.18 19.97 -0.77 19.2 0 19.08 -0.89 18.19 19.97 -0.76 19.21 0 19.23 -0.94 18.29 20.04 -0.76 19.28 0 19.39 -0.89 18.5 20.16 -0.68 19.48 0 19.39 -0.88 18.51 20.15 -0.67 19.48 0 19.58 -0.89 18.69 20.56 -0.63 19.93 Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. UL T BASE represents the ultimate development base model. UL T PRO represents the ultimate development proposed model. Top Width (ft.} ULT BASE 6 UL T PRO-ULT BASE 1014.96 -587.76 0 368.81 -292.45 1058.88 -646.95 0 393.48 -326.96 1157.21 -718.31 0 82.32 -22.09 473.74 -387.48 0 3182.33 -2699.56 3692.87 -474.23 0 3517.87 -1983.32 4413.13 -813.25 0 3520.8 -3493.63 4413.97 -811 .1 0 3625.93 -3598.76 4414.91 -680.73 0 3626.8 -983.67 4415.22 -679.44 0 2001.95 -1297.98 2855.06 -681.55 0 2004.53 -1 291.17 2855.95 -675.84 0 2013.8 -1254.38 2860.05 -666.57 0 2010.97 -1 254.2 2859.85 -671.36 0 417.98 -254.62 888.46 -438.98 0 527.87 -328.42 1038.14 -478.08 0 42.61 -2.23 43 -0.14 0 42.98 -2.16 43 0 ULT PRO 427.2 76.36 411.93 66.52 438.9 60.23 86.26 482.77 32 18.64 1534.55 3599.88 27.17 3602.87 27.1 7 3734.18 2643.13 3735.78 703.97 2173.51 713.36 2180.11 759.42 2193.48 756.77 2188.49 163.36 449.48 199.45 560.06 40.38 42.86 40.82 43 4/5 ( (/) 0 z <{ Ll.J 0 SEC NO 16789 16789 16821 16821 16855 16855 18094 18094 18874 18874 18934 18934 18939 18939 Water Surface Elevation and Top Width Comparison Ultimate Base Model vs Ultimate Proposed Model Water Surface Elevation ( ft.) Top Width {ft.) ULTBASE 6 ULT PRO ULT BASE 6 ULT PRO-ULT BASE ULT PRO-ULT BASE 0 0 19.6 -0.89 18.71 635.7 -406.49 20.61 -0.63 19.98 1865.67 -955.09 0 0 19.6 -0.88 18.72 643.58 -412.64 20.61 -0.63 19.98 1891.9 -975.73 0 0 19.62 -0.9 18.72 3328.04 -2062.04 20.62 -0.62 20 4246 -15.04 0 0 19.72 -0.3 19.42 3394.05 -1195.83 20.63 -0.56 20.07 4542 -0.65 0 0 19.97 -0.17 19.8 52.95 -5.86 20.86 -0.44 20.42 61 0 0 0 20.01 -0.16 19.85 22.66 -0.07 20.9 -0.42 20.48 26.17 -3.32 0 0 20.09 -0.16 19.93 1120 -98.2 21.05 -0.4 20.65 1120 0 0 0 18963 20.1 -0.15 19.95 1120 -64.18 18963 21.05 -0.39 20.66 1120 0 ( (/) a:: Notes: Each SECNO listed represents the 10-and 100-year storms, respectively. UL T BASE represents the ultimate development base model. UL T PRO represents the ultimate development proposed model. ULT PRO 229.21 910.58 230.94 916.17 1266 4230.96 2198.22 4541.35 47.09 61 22 .59 22.85 1021.8 1120 1055.82 1120 515 HCFCO Unit F216-00-00 ENGINEER'S COST ESTIMATE 1/26/2000 PROJECT: Little Cedar Bayou SH 146 to SPRR Regional Study ( UNIT SPECIFICATION UNIT PRICE ITEM SECTION BID IN NO. NUMBER UNIT ITEM DESCRIPTION QUANTITY UNIT NUMBERS AMOUNT BID 1181-01 01181 PRIVATE UTILITIES 3 EA 100,000.00 $300,000.00 UCAR (6" at SPRR) Exxon (2-8" lines at 16th St) 2200-01 02200 SITE PREPARATION & RESTORATION EA 50,000.00 $50,000.00 2232-01 02232 SELECTIVE CLEARING 0.5 AC 5,500.00 $2,750.00 2233-01 02233 CLEARING & GRUBBING 14 AC 3,300.00 $46,200.00 2315-02 02315 EXCAVATION & OFF-SITE DISPOSAL 210,130 CY 5.00 $1 ,050,650.00 From Cl card in HEC-2 2361-01 02361 FILTER FABRIC FENCE 1,350 LF 2.1 5 $2,902.50 Pond only 2361-02 02361 REINFORCED FILTER FABRIC FENCE 1,350 LF 2.70 $3,645.00 Pond only 2365-01 02365 STABLIZED CONSTRUCTION EXIT 200 SY 10.50 :52,100.00 ( 2376-03 02376 CONCRETE CHANNEL LINING, 6" 835 SY 40.00 $33,400.00 NOMINAL THICKNESS Under Spencer Highway 2377-30 02377 20' x 4' CONCRETE LOW FLOW 96 LF 240.00 $23,040.00 Under Spencer Highway 292 1-02 02921 TURF ESTABLISHMENT-80,300 SY 0.25 $20,075.00 HYDROSEEDING WITH MULCH 55,900 for pond and 24,400 for channel 2921-03 02921 TURF ESTABLISHMENT-8 AC 830.00 $6,640.00 OVERSEEDING 2921-04 02921 TURF ESTABLISHMENT-SODDING 11 ,000 SY 4.00 $44,000.00 Slopes of pond and channel Subtotal $1 ,585,402.50 Contigency (15%) $237,810.38 Total Construction Cost $1,823,212.88 Engineering and Administration ( 10%) $182,321 .29 TOTAL COST $2,005,534.16 ( F:\67603\HYOROILCBILINEOEnCOSTEST.XLS HCFCD Unit F216-00-00 ENGINEER'S COST ESTIMATE 1/26/2000 PROJECT: Little Cedar Bayou SH 146 to Sens Road Regional Study ( UNIT SPECIFICATION UNIT PRICE ITEM SECTION BID IN NO. NUMBER UNIT ITEM DESCRIPTION QUANTITY UNIT NUMBERS AMOUNT BID 1181-01 01181 PRIVATE UTILITIES LS 1 ,200,000.00 $1,200,000.00 UCAR (6" line at SPRR) Exxon (2-8" lines at 16th St) Enron (2-6" lines at SPRR) Duke (6" line at SPRR) Praxair (6" line at SPRR) Mobil (8" line at SPRR) Channel Industries (30" line at SPRR) 2200-01 02200 SITE PREPARATION & RESTORATION EA 50,000.00 $50,000.00 2232-01 02232 SELECTIVE CLEARING 0.5 AC 5,500.00 $2,750.00 2233-01 02233 CLEARING & GRUBBING 14 AC 3,300.00 $46,200.00 2315-02 02315 EXCAVATION & OFF-SITE DISPOSAL 212,040 CY 5.00 $1,060,200.00 From Cl card in HEC-2 2361-01 02361 FILTER FABRIC FENCE 1,350 LF 2.15 $2,902.50 Pond only ( 2361 -02 02361 REINFORCED FILTER FABRIC FENCE 1,350 LF 2.70 $3,645.00 Pond only 2365-01 02365 STABLIZED CONSTRUCTI ON EXIT 200 SY 10.50 $2,100.00 2376-03 02376 CONCRETE CHANNEL LINING, 6" 830 SY 40.00 $33,200.00 NOMINAL THICKN ESS Under Spencer Highway 2377-30 02377 20' x 4' CONCRETE LOW FLOW 96 LF 240.00 $23,040.00 Under Spencer Highway 2921-02 02921 TURF ESTABLISHMENT -90,100 SY 0.25 $22.525.00 HYDROSEEDING WITH MULCH 55,900 for pond and 34,200 for channel 2921 -03 02921 TURF ESTABLISHMENT -9 AC 830.00 $7,470.00 OVERSEEDING 2921 -04 02921 TURF ESTABLISHMENT-SODDING 13,900 SY 4.00 $55,600.00 Slopes of pond and channel Subtotal $2 ,509,632.50 Contigency (15%) $376,444.88 ( Total Construction Cost $2,886,077.38 Engineering and Administra tion (1 0%) $288,607.74 TOTAL COST $3,17 4,685.11 F:\67603\HYORO\LCB\LINEDEnCOSTEST.XLS List of Files Little Cedar Bayou ( E xisting M odels from HCFCD F21600FH.FCD ......................................................... HCFCD Flood Hazard HEC-2 Model F2 1600FH.FEM .......................................................... FEMA Flood Hazard HEC-2 Model F21600FW.FEM ............................................................... FEMA Floodway HEC-2 Model F21600SO.FCD ............................................................................... Routing HEC-2 Model F216-l0.FCD ................................................................................... 10 Year HEC-1 Model F216-l OO.FCD ............................................................................... 100 Year HEC-1 Model Corrected Existing Models F216REV.FCD ......................................... Corrected Existing Flood Hazard HEC-2 Model 10REV.BBI ....................................................... Corrected Existing 10 Year HEC-1 Model lOOREV.BBI ................................................... Corrected Existing 100 Year HEC-1 Model Upda ted Base Models JKFNEW6.BBI ......................................................... Updated Flood Hazard HEC-2 Model RTJKF6.BBI ........................................................................... Base Routing HEC-2 Model 10JKF6.IH1 .............................................................................. 10 Year Base HEC-1 Model 100JKF6.IH l .......................................................................... lOO Year Base HEC-1 Model Proposed Models Improvements between SH 146 and SPRR SEDIM2.BBI... ........................................................ Proposed Flood Hazard HEC-2 Model RTSEDIM2.BBI... ............................................................ Proposed Routing HEC-2 Model 10SED2.IHl ...................................................................... Proposed 10 Year HEC-1 Model 1 OOSED2.IH 1 .................................................................. Proposed l 00 Year HEC-l Model Improvements between SH 146 and Sens Road SEDIMJ.BBI... ........................................................ Proposed Flood Hazard HEC-2 Model RTSEDIM3.BBI... ............................................................ Proposed Routing HEC-2 Model lOSED3.IHl ...................................................................... Proposed 10 Year HEC-1 Model 1 OOSED3 .IH l .................................................................. Proposed l 00 Year HEC-1 Model Ultimate Models UL TBASE.BBI ................................................ Ultimate Base Flood Hazard HEC-2 Model UL TPSED.BBI... ...................................... Ultimate Proposed Flood Hazard HEC-2 Model lOUl T.IHI ................................................................ Ultimate Base 10 Year HEC-l Model I lOOUL T.IH 1 ............................................................ Ultimate Base 100 Year HEC-1 Model lOULTP.IHl ....................................................... UltimateProposed lOYearHEC-1 Model lOOULTP.IHl.. ................................................. Ultimate Proposed 100 Year HEC-1 Model ( ( ; ( Binkley 8c: Bartield, Inc., Consulting Engineers 1710 Seam.ist Drive 0 Houston. Texas 77008-3189 (713) 869·3433 FAX (713) 869-6702 Mr. Burton Johnson, PE Planning Department Manager Harris County Flood Control District 9900 Northwest Freeway Houston, TX 77092 September 14, 2000 Re: Amendment to: Watershed Study for the Little Cedar Bayou watershed Project Identification No. F216-00-00-Y001 Dear Mr. Johnson: The following report summarizes our recent analysis of the effects of full development of the Little Cedar Bayou watershed on the detention capacity of the linear detention pond described in the main body of this report. Introduction and Scope: The study described in the main body of this report identified improvements to Little Cedar Bayou consisting of straightening and lowering of the flow line upstream of State Highway 146, and continuing upstream to Sens Road. This proposed improvement resulted in lowering of the water surface and reductions of the flooded areas upstream of SH 146. In order to mitigate any downstream increases in water surface, which might be caused by these improvements, a linear detention pond was modeled between State Highway 146 and Spencer Highway. Additional analysis showed that the proposed channel improvements and detention would continue to function properly and produce no adverse effects under conditions of full development of the watershed. In the process of deciding whether to move forward with the channel improvements and linear detention, officials of the Harris County Flood Control District and the City of LaPorte felt it was necessary to determine whether the proposed linear detention pond will be large enough to mitigate all the effects of full development of the watershed. This amendment to the report addresses that question. Houston Dallas Austin ( ( ( Methodology: Mr. Burton Johnson, P.E. Page 2 of 5 September 14. 2000 In order to determine the effects of full watershed development, modeling studies were done by revising the watershed parameters in the HEC-1 models in order to calculate flows based on 100% development of the watershed. The increased flows that were produced overwhelmed the 225' wide linear detention pond, proving it too small to mitigate the effects of 100% development of the Little Cedar Bayou watershed. The models were then modified to reflect a larger size pond, but it was apparent that the structure of the models was not appropriate to show the full routing benefits of a larger pond. To overcome the structural difficulty in the models, the HEC-1 models were modified to split the LCB-1B subwatershed into two pieces. The portion of LCB-1B east of State Highway 146 was modeled as LCB-1 C as shown in Exhibit A -1. The areas of the revised subwatersheds were revised accordingly. Based on maps of the area, LCB-1 B was modeled to be slightly less than ~ developed, while LCB-1 C was modeled as fully developed. The structure of the HEC-1 models was changed to route the outflow from LCB-1 B through the proposed linear detention pond, while the outflow from LCB-1C was added to Little Cedar Bayou downstream of the linear detention pond. Using these restructured HEC-1 models, a new Base Model was produced which reflects the revised model structure of Little Cedar Bayou. Following the creation of the restructured Base Model, 3 separate models were produced reflecting different possible conditions of development. For reference, these models will be referred to as: Base, Model 1, Model 2, and Model 3. Throughout the analysis, the development parameters were not varied for LCB-1C or for LCB-2, since additional development in these areas is not likely to be mitigated by a detention pond upstream of the developed areas. The methodology is the same for each of the models: the watershed parameters were varied to reflect the desired level of development, and CI cards were used in the HEC-2 models to reflect changes in channel width or changes in the width of the linear detention pond. Storage-volume relationships for HEC-1 routing purposes were calculated using HEC-2 routing models. The following discussion lists the key analysis elements contained in each model. Models 1, 2, and 3 are identical to the Base Model, except for the modifications listed below: Base Model: This is the restructured Base Model which splits LCB-1 B into two pieces. This model contains the 225' wide linear detention pond and channel improvements up to Sens Road that are described in the main body of the report. Filenames: 10 Year: 100 Year: Routing: 10BASE.IH1 1 OOBASE.IH 1 RTJKF6.BBI ( ( ( Effective: BASEH2.BBI Modell: Mr. Burton Johnson. P.E. Page 3 of 5 September 14. 2000 This model was modified to reflect fully developed conditions in LCB-1 B. Filenames: Model2: 10 Year: 100 Year: Routing: Effective: Dl-1 O.IH1 D1 -100.IH1 RTFULL.BBI (ci cards off) FULLH2.BBI ( ci cards off) This model reflects fully developed conditions for LCB-1 B and changes the width of the proposed linear detention pond from 225' to 500'. Filenames: Model3: 10 Year: 100 Year: Routing: Effective: D2-10.IH1 D2-100.IH1 R TFULL.BBI ( ci cards field 7) FULLH2.BBI ( ci cards field 7) This model reflects fully developed conditions for LCB-1B and LCB-lA, along with a 500' width for the linear detention pond. A widened channel (40' bottom) was included upstream of the detention pond to Sens Road. Bridge modeling was modified to reflect the revised channel width. The widened channel is included in order for the modeling parameters to be consistent. Percent of Channel Conveyance is one of the watershed calculation parameters. and if this item is updated to 90%, then routing calculations should be made using a channel section that provides roughly the same conveyance. Filenames: 10 Year: 100 Year: Routing: Effective: D3-1 O.IHI D3-1 OO.IHl I FULLH2.BBI lRTFULL.BBI Watershed parameter calculations and prorated flows for each of these models is included in Appendices AI through A4 in this amendment. All computer files listed above are included on the disk attached to this amendment. ( ( ( Mr. Burton Johnson, P.E. Page 4 of 5 September 14, 2000 Results: The output from the models described above has been tabulated for comparison purposes in spreadsheet format in Attachment A to this Amendment. The model output is shown in each labeled column, and the output from Models 1, 2, and 3 are compared to the output from the Base Model by subtracting the value of the Base Model output. For example, the column labeled "SECNO" contains the HEC-2 section identifier, the column labeled "BASE" contains output from the Base Model, the column labeled "1" contains output from Model 1, etc. The column labeled "I-BASE" contains the value obtained by subtracting the output value of the Base Model from the output value of Model 1. The flow (Q) and water surface elevations (CWSEL) are compared in similar manners. The first line of data for each SECNO is from the 10 year event; the second line is from the 100 year event. Referring to Attachment A, it is apparent that there are water surface increases from SECNO 5555 to SECNO 8432 in Model 1. This indicates that the 225' wide linear detention pond is not large enough to mitigate all excess flows from full development of LCB-1 B. Attachment A also shows that there are no water surface increases between the Base Model and Model 2, indicating that a 500' wide linear detention pond is large enough to offset full development of LCB-1 B. Again referring to Attachment A, there are increases in water surface elevation between the Base Model and Model 3 from SECNO 4778 to SECNO 8712. This indicates that a 500' wide linear detention pond will not mitigate all excess flows from the combined effects of full development of LCB-1 B and LCB-1 A, along with the associated channel and bridge widening. Conclusions: 1. The stated conclusions in the main body of the report are correct; the 225' wide linear detention pond will mitigate the effects of the proposed channel improvements to Sens Road. 2. The 225' wide linear detention pond will not mitigate the combined effects of full development of LCB-1 B and the channel improvements to Sens Road described in the main body ofthe report. " .). By widening the proposed linear detention pond from 225' to 500', the larger detention pond will mitigate the combined effects of full development of LCB 1-B and the channel improvements to Sens Road described in the main body of the report. In order for the 500' wide linear detention pond to be fully effective, it is imperative that all developed areas withiin LCB-1 B be drained into the linear detention pond. Any flows not routed through the pond will greatly reduce the detention effect. ( ( ( Mr. Burton Johnson, P.E. Page 5 of 5 September 14, 2000 Widening the linear detention pond from 225' to 500' will require the addition of the following quantities to the construction estimate contained in the main body of the report: ITEM CLEARING AND GRUBBING EXCAVATION & DISPOSAL TURF ESTABLISHMENT QUANTITY UNIT PRICE 4 ACRES 3,300.00 334,000 CY 5.00 5,000 SY 0.25 SUBTOTAL CONTINGENCY (15%) TOTAL ADDITIONAL COST AMOUNT $13 ,200 $1,670,000 $1.250 $1,684,450 $252.668 $1.937,] 18 4. Full development of LCB-lB, LCBI-A, combined with the effects of widening the upstream reaches of Little Cedar Bayou and the affected bridges to 40', will overwhelm the 500' wide linear detention pond. Additional detention will be required to mitigate these conditions. 4. Any channel improvements or development upstream of LCB-1 B will greatly affect the capacity of the linear detention pond. If a linear detention pond is to be planned to provide mitigation for full development, it should be designed in conjunction with a specific plan for drainage of the developed areas. The linear detention pond should be fully coordinated with the design of any other channel improvements in the Little Cedar Bayou watershed. Sincerely, BINKLEY & BARFIELD, INC. Consulting Engineers ~~~ John G. Fowler, P.E. Senior Project Manager ( ( \ EXHIBIT A-1 ( ( ( 0 0 I ..., I 0> 9 i ORT .. NOTE: ~ wartr. Tank ,2'' ,J I ~-· ;., r ui ••• I i :I i ~ ~~~ !--~.··----.·· ·~"--.-~.: ~ .. ~.~--~--~~-~~~-~ -----'ii,ii · LEGEND: WATERSHED BOUNDARY LCB-2 WATERSHED SUBAREA WATERSHED BOUNDARIES BASED ON F1 01 -00-00 PLANS j z~ -·:<e·CD :VJ 0 RE VI SED WATERSHED BO UNDARIES N.T.S. ~----------------Binkley & Barfield. Inc. Consulting Engineers EX HIBIT A-' ( ( ( ATTACHMENT A Comparison of Results ----"-- secNo I ll FttxF ·r !:i~Pt1At:"\' ~~:.~ ... ~.:~t··xJcltx"J:.a .. ·-~ .. -·-x .L.~~-.--\1:'\< .. i)tP~r:: .. J.·~·;/:~,..I ·'··r<t,:cP::.··.~, sr~AstAPt·iA."'"'~lu-"·-"·r·x"At ... x'P 'a';;_~ ~x·~·-... ~· , ··x·Rix .. , ·t·x 1 0 0 I 528; -5281 1818 1818 1903 1903 1953 1~~3r 19901 -199Cij 2040! ---~ ?.g~-~ I ~ 2910 2910 3660 --··----1-3660 ~~~~i-~Jj~L: -~~~~~~:~-~~~~ _ ~~f~l : -~Q~I -~ ??~ 1---~-~1 -283 1_~6~1 --4.95 + • • - 1576 2251 -216 -------210 ~~~~ 1---:~¥~ , __ u~~~---~~~~~---~~~~~--~:;~ 1374 1921 ~U!I -----~~~~1----~~~~~---~~~~· ---170 -123 . ~~~~~-. -~::~ -0.371 -0}3t --_3.96·. . -0.571 3.72: :u~ ~~~~u~ :~ 1~( -: --ut -------------------·-·-----l · . -Q-~~~-----2-~~ _ ~.2:I~I ____ ?-?~L -0.31 1.01 -o.57r 6.81 ----5.03~1 ----~:~~-1 --:~~~~~--t§~ -0.52, ---"[ -~-~~~- . -Q-?~1 - -0.42 -0.58 -0.43 2.72 3.86 3.39 4.52 5.76 6.96 5.9 7.12 ~~~1!__~-~~t~I-~-~~:~~J!E-~;~~L -~Jj~[~_ .~Hjl ~---_ i~~11=-~ 6li t~~ --~~~~-" -~~~~:~~~~~~:~~E~----t~!=~-~-~~:~~ ~ ~ t~~ ~~?~J---~3~ 1921 -144 1~?~1 ----~1~t 1921 r -144 ~;~t l ---~~~~· -- ----~~~~~--~u~ ~~~~1---:~~~t-----~~;~1 ----~H~I --~;~~~--~:~11--~~i~ 6.13 7.3 --=2-?~~--~·?Zf-_-.2-~ZI-___ ?-~? -0.58 7.03 -0.43 7.18 -·-~~~~~ -276 I _~Q98 1777 -249 r-1672 --~!?Q f--120~---6.5~1 --0.41 6.161_:2-??j----~-~!f----2:~?1 ---~-~~ -123 1798 , 7.661 -0.32 7.34 -0.59 1.01 -o.43r 7.23 -----·---·------. H~~-----:~~~1=~~~~~r----~~~~r ~~~~r---11!1 ____ ~6~~1--t~11 ---~K~~~ -----t~~~ ---~t.~l----~:~~ 1777 -249 1672 ____:!_?Q.I _J2041 8.03 -1231 1798 9.41 -0.4H.63 -0.35 9.061----:-· 7.23 8.78 -0.54 -0.56 7.49 8.85 123~1 -27680~~ --·------- -:;:~! :~~r · J!~---~:~~E=j~-_:_ l~~L~ -~~~ = :U~~ ~JjLJ~~ =~aaF-=;~~ ==wF]J~f -:. ~·~~ ~::::t --:~::--~~ ~~-:::; -=-~: ~ :::( ?:~~-:~:, =:~::: --:-::. ·. -~;~~--:~::: _-;~;::;-· -:~---::: 5555 1385 114: 1499 701 1455' 2251 1610 12.1 i 0.12 --~-12.22 . -0.04 12.06: 0.27 12.37 I Note: Zero values display as blanks Page 1 of 6 ,-... -.._ ..-. ..... SEC NO 5616 1160: -61 : 1099 -1 59! 1001 ' -34 11261 11 .18' -0.28~ --16.91---6.68 ' 10.5. -0.25 10.93 5616 1385\ _1_1~1 . 1~9 _ -· __ ?oi 1455 225 1610· !2.14 i _ 9.12: 12.~~! ~9-o4 ; 12 .1( 6.28 12.42 ~mi 1~~~~ -'~~~ -:mr ~ -:~r ,~~~ ,6~ _ 1m I -1H1 3~~ --_-.ttr ]~~~ =J~m ·"t~l :~~~ I ~:~1 :~~~ -==:-~~r--}~~~ _~_-_::~! -~IJi~ ____ i~! -~_1~~~ :: ::~!~ ~---11~ :~~'~"L ~~t l~!JI_ -ot~l 1~~~ ~~Q4j 1Q~~ --~! ...!Q!4 _~~---~~ol. --~?. _____ ~Q?? _1_1.22 _ -o.~~r-_...!~93 -0.6~---!~~i ____ ...::Q-~~1 -· !Q-~? 5904 ~~85 ·--. -50 --~35 --~-_!~?_4,_ ·-__ 108 ---~~~ 12.17 --0.14 --12.31 -0.02 ---~15 -----0.?_9 12.46 59401 1o35 ---~1 --1614 ----95 ___ 9461 ____ 42 ·-1677 --1 1)2 ---~0.28 10.94 ----:o:6sr-------w:54 ---6.251 · 16.97 -s94or --1385 ·--5o --1335 -61 -1324 -·1oa~493 12.11 o.14 12.31 ---o.o2 --12:~5 ---o.3l 12.47 .. --. ·---··· -----------------------------!--- -· 6151 1 · ·-----94o --42 --_1o11 ---f1.24 ---~o.2s ,__10.96 ----·--o.6s~0.56 -----6.24 -11 . ·--_§1~1 1 ---1324 --·168 -~ __ _!493 --~ =·_qJ~ ---12.~~-=-~=:§9~ ·_ 12.!2 ~-_-_~0-~------12:5 I -!!!t :~ ::~ -~~! ---:;;~ ~~~! =:·-~:~: --~J~: ~ ::~ =:-:: ;: ---1::~:-~ :::--:::~-::: =-~:~;! __ :::; 6696 1385 -50 1335 -61 1324 108 1493 12.29 0.12 12.41 -0.03 12.26 0.3 12.59 --. • ----·---------------.:..c:..:.. _______ ----------------------------·------· -- ----------------------------------------------:=------------------- . ------ 6746 1385 -50 1335 -61 1324 108 1493 12.35 0.12 12.47 -0.03 12.32 0.31 12.66 -·--· -. -. --------------------------------------------....... ------------·---·---------------------r --------------------------684ol-1035 -21 1014 -95 940 42 1011 11.4 -0.28 11.12 -0.68 10.12 -o.22 11.18 =~:::~:: ·;:::F~-_:: ---::: ~ ~::;~-'::_ ;:;;,:~-:;:: ~ ~:: _:~ ~:: --::;;~-,~~: = _-_;~~; ___ 68~~, 1385 . _-50 ___ _.1~35 _______ -§1 ___ 1_324 .. ___ 10_~ ____ 14_93 ____ 1_2...:~1 -__ Q;~1 -_ _!?.52 ____ .:_Q._Q4 . _1?-~? __ -0}2j __ 12}3 6959: 1035 ~ .. --?i 1 1Q~4j -$5 94ol 4?: 1077: 1~.41 1 -0.~8 i1.1~ --6.68 i Hi?~~ -9.22· 11.1 9 6959 1385 -50; 1335 -61 1324 1081 1493' 12.44, 0.11 12.55 j -0.04: 12.4 0.32 12.76 i Note: Zero values display as blanks Page 2 of 6 --.. -.... .--., secNo 1 · sxg·g-~,~·-·l'~Bii<E~r-,··,~-·-.:.···:·:~ ... \~XRX'8-r4l·,·t.; ... ·;:tiL··~-{\; i::itxtrf"t~'~;r\L~I~-4-R'TAP::-:~v··-···r:lrlKP.'5i~~-~~~-~-.;;-·-...... .l r·x-R-t-A'P ..... ~r.:-;K .. ;x~~ .. ·--~a..,x!J·Rii'AP··a--x 1 7434; 7434 74941 74941 ' ~514 j 75141 ?5~4 1 1035 1385 1035 1385 ---~~61 · --~~~g~·--95 -61 --~~M-----~~~gl --·-. ~~~ -~~61--. ~~~~· ·--·--95 -61 1324' 940 1324 940 1324 940 1324 42 108 42 108 42 108 1077 ----~---1493 1077 -----·--1493 1077 .. ---I -·--1493 11 .55 12.6 11 .55 12.59 11 .55 12.59 -0.26 0.09 11.28: 1?.68i -~~~1 -----H~~·- --Qt~l---H:~; -Q.27 1--~!·?~ 0.09 12.68 -<;>.~~~ ~ Q.~8; -0.051 12.54 -. -· ---- --------------~K~~~-----~~:~~·-- -0.19 0.32 :Q.!~; 0.32 : -.. -··1 . ---i. -JQ-~~~---Q.!~I 12.54 0.32• -0.66 -0.05 -Q-~§1 ---1Q-~~ -0.06 12.53 -0.19 0.31 ~5~4 '1 7899 7899 ' ;g:rl· : ~~: >:~1: ;~_:_~~~ ~ :_= -~ --~·~~ --~-~::1~ ):1--~i~: · -_ :_i~r ~:i~ ~ ~ i~[ :~:~-: --~i~r ! ~~;~J . 1~~~ --~-.-. .3) -_--~1t~ ----2~1 1~~~ ~~Z --~-1~~~:-->~~:~-~ :-~~~~. ~ H:~~ -·:6%~ -~---H:~~ -g:~-~~ ~i~~~-: -,~~L -.. n :~~1~ -_ :::~-~~ ~-,~~:: · -i~~ ~-::; -__:jt,'~ -J~ ~_-1HF-~ ~;~~ ~JH~--t~~~ . ---i --------------·-------·--------------------------------------------·--. ---1·· . ~?~4,_ -?~~ . ___ ?~----~!~ -· ____ _-?~ --·-. -~§E? ---1?~ __ 1Q!§ ---~?-!? .. -.Q:~~ ---~1·~~ . _:0_:?_ __ 1 !-~? -Q.Q~i -:::1: ·;:~~--~~;-~=----2:-~--~::~~-~-:-::~ ::::~~~~:~=--_!::: 1 ~~:-~~--;:;~ -:~~:----·_;:::! -8364: ---1 1§.? _____ _l? ___ 1)48 ------. __ § -=~]}7!-~ 1~~~----1354 :-==-~~-~_1 ~-~ .. Qi>?. -----~3-~§ ·. --~-:il-=.9?. =-~:[5~ ~-·--Q:~41 11 .35 12.91 11.36 12.92 11.36 12.91 11.36 12.9 11.39 12.95 11.47 13.03 11.96 13.99 12.06 14.09 12.14 14.27 12.11 14.25 · ~~~1 -~ ,~~~~-J~1 __ ,~1~f~ ~2~ ~-~:,~r --1~~ -J~~ --. u~~1 --J~r ,~~r1 -:~~~r ur . Q.Q~; -~~-!~-~~ 0.94: .. 15.32 L 84321 891 ! 23 9141 -25 866, 124, 10151 12.58, -0.23 12.35 j -0.75 11 .83j 0.09 12.67 8432 1165 -17 1148! 6, 1171 _ 189 13541 14.39! 0.03 14.42 -0.05 14.34' 0.94 15.33 I Note: Zero values display as blanks Page 3 of6 -.. SEC NO 8461 8461 ~7121 8712\ I 1Qq~?l 100121 ' n/a j 891 1 1165 576 791 nla I n/a I _ _[ __ 23 -17 nla nla 1~1~1 --~?~ ----~~1 ----j~~l -----~!~ 564 794 ,-..... n/a I 1Q15 i n/a i I I n/a 13541 nfa -I a~ I--~~~~ :JH~I 356 477 932 1268 14.33 ~-----15.55 n/a 12.35 I -I ~~~ ------1~~4~1 -0.24 ·----~2_:~ l 0.04 14.51 n/a 11.83 n/a n/a 14.33, n/a -Q-!.~1----!~~~1----Q-Q~; -0.04. 14.43 0.93. ---··- . I -1 .81 -1.63 -----U:~~I --J~~ 11.99 14.43 -1.51 1 -0.141 ~q~ggl · ___ "-'~ -~-~~-~L=~~~~I-~~ J=~~---~ll l-_-~~~~-J~ __ J;~~t~~-=1--~~~;~_J _---t~~ll-~~: -_ 1-==j4.H ~-~;: I 10900 11124 11124 11174 11174 11327 11327 n/a ---%~--~=~ ~ii_J~-~~1~~~---~: ~:L~~-:J~1 ~~~~~7: __ l-~~1~~~~~~~~~ -~ %:_ .t ~:~a=~~rJ ~~-,. ~~r:= *;: · ' -2.:33! -6.851 I ~~~~F~ _ -~~~-----:~~~--~=~~-~~~----· t~l-~-~~~~t~-=t;~j!_-~_~_]l~ii[-~ --~t~~ -=ruiE~-1~1---rt~~c 1223 ~~~~-. ---~1-------~~~1 -----~~1 -----~:~\---. ~~j 890 15.21 16.31 ~~:~~~--~~~~~~1-~-~JJ~l-~~ a~~~~-:~-_~~:~~~ ---------·· ----------------------.. ---.. , _J~-85 ____ -?-Q~ __ 1~2:§ __ -_?17 --~3.4~----?-?~1 16.9~---:~66 ---15.25 _-1.76 ____ J§~ ---1_.171 ~~~~~ ~ --~~~~-~~-~ -~~~-;~~~ ----;F~--~~--~l~L~ -~~~~[---~~~~ -- 12.66 15.32 12.82 15.4 12.82 15.41 12.83 15.41 12.83 15.41 12.77 15.37 12.88 15.42 13.49 15.74 U~~~[~~~J~ __ 1~ ;~: __ J =-~E= ~f ,m -'~~~ ~-:~,~l ~ :~;~ __=1~~: -~ :U~i· l~~~ . :u1~[ · ·1I~ =--=] ==~ -~=-=-~~ ~-~*~~r~~:~---~~~:: ~~~: --:~¥. -~~ ~ }ni • J ~~J ---~--------1---------------------------------------------------.--------_!??~9._ ~7~r----5 ---~?!i r----=~ ---~§~ -----48~f-----~~? ~5.9~~----_?:_Q1 __ 13.9~ _...:.?.25, ___ _J~.§~ -__-_?_._3~i -~~-§~ 122801 540 -4 536 2 542 648 1188 17.01 -1 .65 15.36 -1.73 15.28 -1.2 ' 15.81 --I -: --.-----------------1--------------------------------:----·--r--. - 1~~?~. 374 j .. _ $~ _ --~?91 --~1 369 ~ -483 _~~I I _ ~~-9~1 -? . j~-~~l -?.24 j -13}i; -2.33. 13.62 12382 540: -4 536: 2 i 542: 648 1188! 17.03 -1.651 15.38; -1.73: 15.3: -1 .21 15.82 Note: Zero values display as blanks Page 4 of6 --.-... SECtJO I At AFE I·· i :..C.ii:iCri( ..-···~:·~·~.~;.. .. ·"":)·& . .;A Jcl/x""J l't'··:.··:~~:·:.··x~· .,. ~~\ .. '.:iliA I·Jll::..#~'"t:'~fj,.::~.::··x··~·:~~.~.l·v~ ..... A.i~l;:i' ~ ·;· ·-.:t."P£~ilt"l-:-rf·~:ii:•r.\li:i~ ... :~., ,:-~~:!"'w .... lx'!i ·','···~ ... ~ ·x :.i. X w * AP a x · I 12414 12414 1?~?~1 124641 ----. ! 12564 12564 I . ' I ' 351 , 41 355 -5 . 346. ;;~L : __ =4! _-_ .;;; ~~ ~o~--;;· 351 ·· --4 --· 35s ----~5r--- 516 1 ___ 4 -----566 ----1 -.. 346 511 4961 847: 666: 1176 ~~~ 1·-· 1 ~~~ 16.01 : 17.07! 16.08 17.16 ~~-~~~ 15.47 --·t~i 1--~ ~~~i -2.22, -1.67: i 13.79 15.4 13.84' . ·-----15.44 13.89 15.48 -2.37 -1.24 I -2.~1 -1 .31 ---! -.?-~?.1 :~:~~~ -2.27 -1 .51 -2.17 ----1----1.48 1;~~1 --~-!~~ =-=-~3f-=-~ _;~~:-.-.. -=~~: ___ ~~!~~~~~-:~~ ~~~~~-u~ 1 ---=H~-~~ ~~·---- -.~~?~~i ___ ?~Q __ .? ____ ?~?. ---=? ----· ?~~ ____ 54r -1~2~~1 . -364 __ __:1 363 1 365 747 14.92 ------~--· 16.31 15.2 ·-·--~ ... _, ___ nO!.~~ .. - 13.64 15.83 13.68 15.86 13.76 15.9 14.79 16.57 15.08 16.78 ~~~~~ !--~--~~~ ~ =~~-1 1 -· --~~~1-----i 1--·--~~61 ---~~~1 -----16~~~-~~:~~~-__ _:~1~~1 --.. H:~~~~i:~~l--~~:6~ :T~~~-. ~~-~~ -0.97 17.37 ~~~?1 1 15371 1 ~--i~_U -~=-~J~ · -~~-~l-~--~ -~~11 =---~ ~~6 1=---J~~~--_ 1~i~l~ · -U:~~I ---=~:~~1 ----1~~:1 :~:~§!--~¥:~1· ·--1 .55 -0.92. -1.65 -1.31 -~5.8~1--.. -!-~~ 17.13 -0.95 ~~1661 -~~ 1!~r ------1 ~-=~~ ~~~~=~=--=~ ·--~66 1 ------~~~1-·-16Y~~ .. -U:~~I ---~1~~ · ~!!I --~:: _ ~~ ~ -; -.=-::! -~•~~~~ ---~! -=~~:E~~ -~!~ ~-~ ;;!! .. ~ -~~: ~;;::: =~-~~~[ ~-;!~!~: · :J; ~--- 1_56~51 -_?8~--1 --~'!?------·-. 28~--?~~ ·--10§.~ -. ~~~?~ ·-----1 .~ .. __ _17.2! -1.26 17.26 -1.45 -0.9 15.9 17.4 15.93 17.49 15.96 17.53 16.1 17.62 16.45 18.06 --1~~~~~ =--~~~. -Jl---.~~~ _ .. __ =--= il~ ----:~fj -::=~~fi __ :[ir~:~~ ...:3;~?~ __ -· :~~~~ ~-H:~~~------~:~~~ -·-~~:~~ - : .. ,. . I . . . . .. I 15725 1?o. _ ~--· 181 . ~?01 564, 7441 1?.6~: -1.48 16:..1? -1.?§ 1 . ~~.or 15725 283 -1 282 ; 283 781 ' 1064 18.52 -1.02: 17.5 -1.03 17.49' I I -1.18 -0.46 Note: Zero values display as blanks Page 5 of6 ----- sEcNo' nrnrnti~rA~94r.m~T.~rTnm~~lt'44~~~~~~~~4~~~~;.;;.,r-~#~ 180 1: 181' I 180 564: 744 1 17.641 -1.481 16.16' -1.56: 16.08 -1 .15 . 283. -1 i 282 . 283 781 [ 1064; 18.5~1 -1.02! 17.51 l -1.03. 17.5\ -0.45 15775 157751 I ------·--. ----~ -.. -' ---·· -. . . ---·-- . -·----.. --. ---. --. ! -I ~~~ ~~~ ----~~~ ---~~ -------~~1 -------------1~~ ·---~~~-----16§1 ----1~!7l -----J~~ · · · ~~:~~ -----~~~~ -·---~~:Ht=----~o~§: ----! --·------·-----·---· ----. -----------·---------------------------·-·-------·---------· --1 - --~~~~§~ -~Ji; =--~~-== ~=~l~~ --~-=--~1~~ ---------~~~~!-_ -~~~~~ -~-<J~~~~--~jr~-~--_1~~r-~~~~ ~~~i~~~-~~~-~t~~~- .;;!~!j~-=-~~F~----=-~~ :~; =-~.~~ ~--~; -;= ::: • --~; ~~~-~=-~:~:=:~ -_:::: ~=-~~~~ 167l~ __ _236 _____ L_ 2~~ _ --~36 . _ --~6 ___ !032 ___ !~:2.! ____ -1.19 17.82 _____ -_1.:2 ____ J7.~!-____ -9_-08 j -~~~~~1:=--~~-H~l--~~-__ J~~~iiU-==~~-~~r -~-.. -~~! ------1~j~~~--1!~o~-~~-~~~"" --~ -~f~l-=~:~~~:; --... ~~:~f 3 16.49 18.08 16.69 18.24 17.05 18.54 17.09 18.58 17.1 18.93 17.14 18.97 -~!!!~; _-n ~~!,~~~:~~ ~= ~ ;~ ==-t~~! ~-: -: ~--,:::1LJ!!: t ! ~;~~;~ ~~~::; :~-~ ~;; --:::: 16855 228 228 228 720 948 19.04 -1.21 17.83 -1.21 17.83 0.01 j 19.05 -----------------·--------------------------------------------------~- ]~~~~-= _ a1 --=-•=----::l~J-==~===1~1 -_ ~JU =~L ~Hl--:_=~~IHF-cnf _ -lH~ -:H~j~-~-~J~:t~ --18874 ---169 -109 109 ---200 309 -18~91 -0.97 17.94 1-----~0.98 --17.93 ------~1.47 -17.44 1887·;\------176 -------------176 -----------176 --'282 -----452 :-----'19.6 ----=o.54 ---19]6 ---0.54 --·-19.06 ----6.4, -19.2 Note: Zero values display as blanks Page 6 of6 ( ( ( APPENDIX AI Base Model ,-.... ,-..... Little Cedar Bayou Watershed HCFCD Unit F216-00-00 Base Model .--... Physical Characteristics for Subwatersheds Subwatershed LC81A LC8 18 LC8 1C LC8 2 Drainage Watershed Length to Channel Overland Channel Area Length Centroid Slope Slope Development Improvement Conveyance Ponding Impervious (sq. mi.) ___ (11)!-)_m ___ . (mi.) .. _ (ft/mi) (Wmi) (%) (%) (%) (%) (%) 0.86 1.34 0.61 0.94 1.7 30 31 30 0 11 0.8727 1.63 0.85 5.1 14.8 49 66 70 0 22 0.3573 1.5 1.03 5.10 14.8 100 100 90 0 35 1.10 1.73 0.76 2.2 9.6 66 37 90 0 29 Subbasin Unitgraph Coefficients Subwatershed L I -J""; Tc+R Lea ;-J.; D Tc R LC8 1A 1.38 20.06 0.63 2.46 1.22 18.84 LC8 18 0.72 4.01 0.38 2.46 0.54 3.46 LC8 1C 0.66 1.83 0.46 2.46 0.41 1.42 LC82 1.17 3.60 0.51 2.46 0.87 2.74 ( ( ( Prorated Flows for Little Cedar Bayou F216-00-00 Base Model Hydrograph SEC NO Reach 10 Year 100 Year (ft) (cfs) (cfs) B (Combined) 0 0 1576 2251 1903 1903 1374 1921 4240 4240 1160 1581 5828 5828.5 1035 1385 A (Combined) 7899 7899.7 891 1165 10012 10012.7 576 791 11174 11174.7 453 640 12098 12098.7 374 540 12414 12414.7 351 510 14246 14249.7 240 364 15321 15324.7 192 299 15635 15638.7 180 283 LCB1A 16620 16623.7 147 236 16855 16855 142 228 18094 18094 121 191 18874 18874 109 170 23280 23280 60 90 Intermediate flows obtained from: ( ( APPENDIXA2 Modell ,.-...., Physical Characteristics for Subwatersheds -. Little Cedar Bayou Watershed HCFCD Unit F216-00-00 Model1 Drainage Watershed length to Channel Overland Channel ..-.... Area length Centroid Slope Slope Development Improvement Conveyance Ponding Impervious Subwatershed (sq. mi.) (mi.) (mi.) (ft/mi) (ft/mi) (%) (%) (%) (%) (%) LC8 1A 0.86 1.34 0.61 0.94 1.7 30 31 30 0 11 LC8 18 0.8727 1.63 0.85 5.1 14.8 100 100 90 0 35 LC8 1C 0.3573 1.5 1.03 5.1 14.8 100 100 90 0 35 LC8 2 1.10 1.73 0.76 2.2 9.6 66 37 90 0 29 Subbasin Unitgraph Coefficients Subwatershed L I ~ Tc+R L ea / -Fs D Tc R LC8 1A 1.38 20.06 0.63 2.46 1.22 18.84 LC8 18 0.72 1.94 0.38 2.46 0.33 1.61 LC8 1C 0.66 1.83 0.46 2.46 0.41 1.42 LC8 2 1.17 3.60 0.51 2.46 0.87 2.74 ( ( ( Prorated Flows for Little Cedar Bayou F216-00-00 Model1 Hydrograph SECNO Reach 10 Year 100 Year (ft) (cfs) (cfs) 8 (Combined) 0 0 1360 2041 1903 1903 1236 1777 4240 4240 1099 1499 5828 5828.5 1014 1335 A (Combined) 7899 7899.7 914 1148 10012 10012.7 587 783 11174 11174.7 460 634 12098 12098.7 379 536 12414 12414.7 355 506 14246 14249.7 242 363 15321 15324.7 193 299 15635 15638.7 181 282 LCB1A 16620 16623.7 147 236 16855 16855 142 228 18094 18094 121 191 18874 18874 109 170 23280 23280 60 90 Intermediate flows obtained from: ( ( ( APPENDIXA3 Model2 ,.-.... - Little Cedar Bayou Watershed HCFCD Unit F216-00-00 Model2 - Physical Characteristics for Subwatersheds Subwatershed LC8 1A LC8 18 LC8 1C LC8 2 Drainage Watershed Length to Channel Overland Channel Area Length Centroid Slope Slope Development Improvement Conveyance Ponding Impervious (sq. mi.) (mi.) (mi.) (ftlmi) (ftlmi) (%) (%) (%) (%) (%) 0.86 1.34 0.61 0.94 1.7 30 31 30 0 11 0.8727 1.63 0.85 5.1 14.8 100 100 90 0 35 0.3573 1.10 1.5 1.73 1.03 0.76 5.1 2.2 14.8 9.6 100 66 100 37 90 90 0 0 35 29 Subbasin Unitgraph Coefficients Subwatershed L I Fs Tc+R Lea f .fs D Tc R LC8 1A 1.38 20.06 0.63 2.46 1.22 18.84 LC8 18 0.72 1.94 0.38 2.46 0.33 1.61 LC8 1C 0.66 1.83 0.46 2.46 0.41 1.42 LC8 2 1.17 3.60 0.51 2.46 0.87 2.74 ( ( ' ( Prorated Flows for Little Cedar Bayou F216-00-00 Model2 Hydrograph SEC NO Reach 10 Year 100 Year (ft) (cfs) (cfs) B (Combined) 0 0 1184 1872 1903 1903 1098 1672 4240 4240 1001 1455 5828 5828.5 940 1324 A (Combined) 7899 7899.7 866 1171 10012 10012.7 564 794 11174 11174.7 445 642 12098 12098.7 369 542 12414 12414.7 346 511 14246 14249.7 238 365 15321 15324.7 191 300 15635 15638.7 180 283 LCB1A 16620 16623.7 147 236 16855 16855 142 228 18094 18094 121 191 18874 18874 109 170 23280 23280 60 90 Intermediate flows obtained from: ( ( ( APPENDIXA4 Model3 - Physical Characteristics for Subwatersheds -- Little Cedar Bayou Watershed HCFCD Unit F216-00-00 Model 3 Drainage Watershed Length to Channel Overland Channel -... Area Length Centroid Slope Slope Development Improvement Conveyance Ponding Impervious Subwatershed (sq. mi.) (mi.) (mi.) (Wmi) (Wmi) (%) (%) (%) (%) (%) LC8 1A 0.86 1.34 0.61 0.94 1.7 100 100 90 0 35 LC8 18 LC8 1C LC8 2 0.8727 0.3573 1.10 Subbasin Unitgraph Coefficients Subwatershed L I ~ LC8 1A 1.38 LC8 18 0.72 LC8 1C 0.66 LC8 2 1.17 1.63 1.5 1.73 Tc+R 3.07 1.94 1.83 3.60 0.85 1.03 0.76 L ca / -.Js 0.63 0.38 0.46 0.51 5.1 5.1 2.2 D 2.46 2.46 2.46 2.46 14.8 14.8 9.6 Tc 0.57 0.33 0.41 0.87 100 100 66 R 2.49 1.61 1.42 2.74 100 100 37 90 90 90 0 0 0 35 35 29 ( ( ( Prorated Flows for Little Cedar Bayou F216-00-00 Model3 Hydrograph SEC NO Reach 10 Year 100 Year (ft) (cfs) (cfs) B (Combined) 0 0 1271 1968 1903 1903 1204 1798 4240 4240 1126 1610 5828 5828.5 1077 1493 A (Combined) 7899 7899.7 1015 1354 10012 10012.7 932 1268 11174 11174.7 890 1223 12098 12098.7 857 1188 12414 12414.7 847 1176 14246 14249.7 787 1111 15321 15324.7 753 1075 15635 15638.7 744 1064 LCB1A 16620 16623.7 715 1032 16855 16855 656 948 18094 18094 414 602 18874 18874 309 452 23280 23280 60 90 Intermediate flows obtained from: