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Home My WebLink AboutBATTLEGROUND ESTATES SUBDIVISION FLOODING (PHASE I) November 15, 2011 Mr. Julian Garza Jr., P.E. Senior Engineer Planning Department City of La Porte 604 West Fairmont Parkway La Porte, Texas 77571 Re: Phase 1 Letter Report to address flooding in the Battleground Estates Area. Dear Mr. Garza: This phase 1 letter report will document the results of Klotz Associates’ analysis of the culvert system along stream F101-00-00 at Avenue P, just west of Lemon Lane (see Exhibit 1 & 2). This report focuses on whether solely upgrading the culvert system at this location will benefit residents in the Battleground Estates area, in regards to past reported structural flooding, by lowering the flood profiles within the adjacent stream, F101-08-00. This letter report provides flooding information for a downstream portion of F101-08-00 that serves as an outfall for drainage from the Battleground Estates addition to its confluence with F101-00-00, see Exhibit 1. F101-00-00 drains an approximate 2.25-mi2 that is bounded to the north by State Highway 225 (SH 225) and to the west by Big Island Slough. Drainage area boundaries are shown in Exhibit 3. Development in the area is mainly large lot residential, some industrial/commercial development along SH 225 and Sens Road., and some smaller lot residential developments including Battleground Estate. An existing-conditions hydraulic model was developed to reflect existing conditions along the waterway with the current structure, (see attached photos). A composite type structure consisting of 2 – 42” corrugated metal pipes (CMP) (upstream portion, shown in Photo 3) feeding into 2 - 8’(H) x 10’(W) reinforced concrete boxes (RCB) (downstream portion, shown in Photo 1). The upstream ends of the concrete boxes have been bricked around the 2 - 42” CMPs, and the 2 – 8’x10’ RCBs outlet into an improved, earthen, trapezoidal channel with a top width of 95-ft, a bottom width of 20-ft, an approximate side slope ratio of 3H:1V, and a depth of approximately 12-ft. The channel upstream of North Avenue P is approximately 5-ft deep, compared to the 12- ft deep ditch downstream or south of Avenue P. To model a proposed solution to the structural flooding in the Battleground Estates area, the upstream portion of the composite structure was replaced with 2 – 8’x10’ RCBs and a portion of F101-00-00 was assumed graded upstream at a reasonable slope to meet existing ground. The earthwork is simply to accommodate the new structures. Hydrology A discharge-drainage area relationship was developed for the watershed using hydrologic data collected from TSARP studied streams in the area (F216-00-00 and F220-00-00). Discharge- drainage area data for evaluating F101-00-00 were extrapolated using regression equations produced from the TSARP data relationship. Model Basis A previous study, (City Wide Drainage Study, Klotz Associates, Inc., January 2009) (CWDS) and a construction drawing for the structure on F101-00-00 at Avenue P (Harris County Flood Control District, December 2009) were used as reference for this report. See Appendix A for construction drawing. Existing-Conditions Model The existing conditions model was built using data from the CWDS, HCFCD Channel Conveyance Improvement construction plans, ESRI’s geographic information systems (GIS), program ArcMap, U.S. Army Corps of Engineers (USACE) HEC-RAS and its GIS extension HEC-GeoRAS, 2010 Aerial photographs (Houston-Galveston Area Council, HGAC), 2008 LiDAR (Harris County Flood Control, HCFCD) which include improvements to the channel south of Avenue P along F101-00-00, and field collected data. The model indicated that flows along segments of F101-00-00 and a small portion of F101-08-00 rise to a level that exceeds the capacity of sections of the drainage channel during the 10-, 50-, and 100-year rainfall events. These capacity limitations producing out of bank occurrences were more frequent upstream of the improved earthen channel north of Avenue P. F101-00-00 upstream and downstream of Avenue P are shown in Photo 4 and Photo 5. The segment of F101-00-00 that flows into the composite structure is an improved, earthen, trapezoidal channel with a top width of 20-ft, a bottom width of 8-ft, an approximate side slope ratio of 3H:1V, and a depth of approximately 5-ft. The capacity of upstream portion of the composite structure is less (approximately 50%) than that of the capacity of the downstream portion of the structure (including the improved open channel, Photo 5). The portion of F101-00- 00 (open channel) that flows into the composite structure (Photo 3) conveys flows at a greater rate than the upstream portion can convey to the downstream portion and improved open channel downstream. The 2 – 42” pipes of the upstream portion of this structure have a total conveyance area of approximately 20-ft2 while the 2 – 8’x10’ boxes of the lower portion have a conveyance area of 160-ft2. This difference in conveyance areas creates a situation that prevents flows from entering the structure resulting in water surface elevations (WSEL) that exceed the limits of the channel banks. The information in Table 1 and the profiles, included as figures, indicate that the larger downstream portion of the structure has sufficient capacity to accept the flows from the upper portion of the composite structure. Proposed-Solution Model The proposed conditions hydraulic model was developed by replacing the upstream portion of the composite structure with structures matching the downstream portion of the composite structure. Adjusting the flowline of F101-00-00 to meet the invert elevation of the proposed RCBs will make full utilization of the structure’s capacity as well as protect the channel during rainfall events that produce higher amounts of runoff. This flowline adjustment and channel improvement extends approximately 215-ft upstream of the proposed RCBs. As shown in Table 1 and the proposed solution profile shown in the figures, the proposed conditions produced a drop in the WSEL at North Avenue P that range from 1.5-ft to 4-ft, however these lower water surface elevations extend no further than 1000-ft upstream of North Avenue P. Due to the localized nature of the lower water surface elevations, only the homes immediately adjacent to North Avenue P would see benefits. These benefits are not noticed in the upper segments of F101-00-00 or in F101-08-00 in the Battleground Estates area due to the conveyance limitation of the channel. Cost Estimate A preliminary construction cost estimate indicates the cost of installing the additional dual 8’x10’ RCB to be approximately $85,000. These costs include removal of the 2 – 42” CMPs, removal of the existing headwall, removal of the existing handrail and the installation of 2 – 8’x10’ RCB (to match the lower portion of this structure), an 11’ wingwall, and excavation for the RCBs. A more detailed explanation of the cost are shown in Table 2. Results and Conclusions: Increasing the capacity of the drainage structure at North Avenue P results in a significant lowering of the water surface elevation in the immediate upstream channel (see Table 1). The Table 1 Existing Proposed Diff.Existing Proposed Diff.Existing Proposed Diff. 15160.24 18.11 23.00 23.00 0.00 23.00 23.00 0.00 23.00 23.00 0.00 14534.39 19.68 21.72 21.72 0.00 21.62 21.62 0.00 21.02 21.41 0.39 13663.88 15.00 19.68 19.65 -0.03 19.64 19.61 -0.03 19.51 19.47 -0.04 12874.61 15.99 19.72 19.46 -0.26 19.62 19.40 -0.22 19.42 19.24 -0.18 12856.96 Culvert ---- - ---- 12856.86 15.90 19.73 19.49 -0.24 19.63 19.39 -0.24 19.43 19.20 -0.23 12707.86 14.91 19.69 19.38 -0.31 19.59 19.23 -0.36 19.39 19.04 -0.35 12690.5 Culvert ---- - ---- 12690.4 14.80 19.70 19.42 -0.28 19.60 19.29 -0.31 19.39 19.09 -0.30 12551.37 14.00 19.64 19.29 -0.35 19.55 19.18 -0.37 19.35 18.58 -0.77 12518.1 Culvert ---- - ---- 12518 13.90 19.66 19.33 -0.33 19.57 19.21 -0.36 19.37 17.03 -2.34 11752.81 14.00 19.53 17.12 -2.41 19.45 16.96 -2.49 19.27 16.56 -2.71 11592.81 13.00 19.48 17.16 -2.32 19.40 16.52 -2.88 19.24 14.99 -4.25 11542.81 14.00 19.48 17.05 -2.43 19.40 16.43 -2.97 19.24 14.93 -4.31 11512.9 Culvert Ave. P --- - ---- 11512.8 8.02 16.77 16.89 0.12 16.24 16.32 0.08 14.79 14.86 0.07 11393.32 Culvert Ave. P --- - ---- 11393.22 7.98 16.60 16.69 0.09 16.11 16.19 0.08 14.70 14.78 0.08 11313.71 7.00 16.76 16.76 0.00 16.25 16.25 0.00 14.82 14.82 0.00 10860.51 7.00 16.71 16.71 0.00 16.20 16.20 0.00 14.77 14.77 0.00 10066.45 7.00 16.45 16.45 0.00 15.94 15.94 0.00 14.51 14.51 0.00 9266.415 7.00 16.20 16.20 0.00 15.68 15.68 0.00 14.25 14.25 0.00 8712.985 7.00 16.00 16.00 0.00 15.48 15.48 0.00 14.05 14.05 0.00 8663.006 7.00 16.01 16.01 0.00 15.48 15.48 0.00 14.04 14.04 0.00 8618.097 Bridge Sens Rd.--- - ---- 8617.997 7.00 15.99 15.99 0.00 15.47 15.47 0.00 14.03 14.03 0.00 8567.992 7.00 15.95 15.95 0.00 15.43 15.43 0.00 13.99 13.99 0.00 7761.743 6.00 15.69 15.69 0.00 15.15 15.15 0.00 13.72 13.72 0.00 6967.946 6.00 15.41 15.41 0.00 14.87 14.87 0.00 13.44 13.44 0.00 6328.381 6.00 15.10 15.10 0.00 14.56 14.56 0.00 13.11 13.11 0.00 6189.11 6.00 15.06 15.06 0.00 14.51 14.51 0.00 13.06 13.06 0.00 6098.921 6.00 15.02 15.02 0.00 14.48 14.48 0.00 13.05 13.05 0.00 5669.789 Culvert Railroad --- - ---- 5669.69 6.00 14.17 14.17 0.00 13.72 13.72 0.00 12.50 12.50 0.00 5619.675 6.00 14.15 14.15 0.00 13.69 13.69 0.00 12.46 12.46 0.00 4819.409 5.00 13.42 13.42 0.00 12.95 12.95 0.00 11.69 11.69 0.00 4019.383 5.00 12.72 12.72 0.00 12.23 12.23 0.00 10.94 10.94 0.00 3323.449 2.66 11.22 11.22 0.00 10.67 10.67 0.00 9.25 9.25 0.00 3276.977 2.00 10.99 10.99 0.00 10.45 10.45 0.00 9.13 9.13 0.00 2949.491 Bridge SH 146 --- - ---- 2949.391 2.00 10.87 10.87 0.00 10.33 10.33 0.00 8.99 8.99 0.00 2896.793 2.00 10.69 10.69 0.00 10.13 10.13 0.00 8.79 8.79 0.00 2469.399 2.02 10.26 10.26 0.00 9.66 9.66 0.00 8.17 8.17 0.00 1756.84 1.00 10.06 10.06 0.00 9.43 9.43 0.00 7.88 7.88 0.00 1467.654 0.00 10.12 10.12 0.00 9.48 9.48 0.00 7.91 7.91 0.00 1297.519 0.00 10.19 10.19 0.00 9.56 9.56 0.00 7.98 7.98 0.00 1247.476 0.00 10.05 10.05 0.00 9.45 9.45 0.00 7.96 7.96 0.00 1160.556 Culvert Railroad --- - ---- 1160.456 0.00 8.86 8.86 0.00 8.34 8.34 0.00 7.04 7.04 0.00 1118.536 0.00 8.80 8.80 0.00 8.29 8.29 0.00 7.00 7.00 0.00 100-yr (1%) Flood Event 50-yr (2%) Flood Event 10-yr (10%) Flood Event Comparison of Computed Water Surface Elevations (CWSEL) between Existing and Proposed Conditions in F101-00-00 at Avenue P HEC-RAS Station Existing Flowline CWSEL (ft)CWSEL (ft)CWSEL (ft) Klotz Associates Project No.: 0127.014.000 November 2011 Phase 1 Preliminary Engineering Report Battleground Estates Flooding Analysis City of La Porte Table 1 Existing Proposed Diff.Existing Proposed Diff.Existing Proposed Diff. 100-yr (1%) Flood Event 50-yr (2%) Flood Event 10-yr (10%) Flood Event Comparison of Computed Water Surface Elevations (CWSEL) between Existing and Proposed Conditions in F101-00-00 at Avenue P HEC-RAS Station Existing Flowline CWSEL (ft)CWSEL (ft)CWSEL (ft) 1059.904 Culvert Unnamed St.--- - ---- 1059.804 0.00 7.10 7.10 0.00 6.82 6.82 0.00 6.01 6.01 0.00 1016.66 0.00 7.13 7.13 0.00 6.83 6.83 0.00 5.98 5.98 0.00 852.7695 0.00 6.74 6.74 0.00 6.45 6.45 0.00 5.64 5.64 0.00 63.6235 0.00 4.13 4.13 0.00 3.89 3.89 0.00 3.23 3.23 0.00 Bold font indicates limits of proposed improvements Klotz Associates Project No.: 0127.014.000 November 2011 Phase 1 Preliminary Engineering Report Battleground Estates Flooding Analysis City of La Porte Table 2 Item No.Description Units Unit Cost QTY Cost 1 Struct Excav (Box)CY $7.00 108 $800.00 2 Rail (Handrail)(TY C)LF $120.00 80 $9,600.00 3 Excavation (Channel)CY $3.45 225 $800.00 4 Conc Box Culv (10 FT X 8 FT)CY $415.00 60 $24,900.00 5 Wingwall (PW)(HW=11 FT)EA $20,000.00 1 $20,000.00 6 One-way Traffic Control HR $37.00 120 $4,400.00 7 Conc Pav (Joint Renif) (6")SY $27.46 100 $2,700.00 8 Riprap (stone protection)(18 IN)CY $86.12 16 $1,400.00 9 Demolition LS $9.00 60 $500.00 $65,000.00 Contingency (30%)$20,000.00 Total $85,000.00 Preliminary Construction Cost Data Klotz Associates Project No.: 0127.014.000 November 2011 Phase 1 Preliminary Engineering Report Battleground Estates Flooding Analysis City of La Porte F101-00-00 F1 0 1 - 0 8 - 0 0 La Porte LSe n s 16 t h 1 0 t h 12 t h Avenue L Avenue P State Hwy 2 2 5 Avenue H E H St a t e H w y 1 4 6 I 14 t h 8t h Tyler 11 t h 1s t 4t h 5t h 6t h 13 t h Ro b i n s o n 26 t h Houston 3r d Al l e y Barbours Cut Hig h w a y 1 4 6 Madison Viola 7t h Old la Port e D Unnamed S t r e e t 9t h Br o a d w a y Al v y S t a t e H w y 1 4 6 S e r v i c e Bois D Arc Deaf Smith San Jacinto Lovinnie Le m o n Va l l e y V i e w Old Strand Mi s s i o n Avenue D 2n d St r a n g Monument La u r a Ash Pine Bexar Cavalry Ea s y Sh i r l e y Cannon Elm Fieldcrest Lo m a x Sa n t a A n n a Alamo Plainbrook Flintlock Dr i v e w a y El m w o o d Oak Ba t t l e v i e w PeachSunset Ridge Elizabeth Mil l e r C u t O f f Milam Du a n e Bowie Parking Lot Po s t T r a i l e r P a r k Ramp Bu c h a n a n St a t e H w y 1 4 6 N o r t h Tr a v i s Fairlane Sky View Bay View South P H Pa r k i n g L o t La Porte E Ho u s t o n 26 t h Fieldcrest Avenue P Br o a d w a y Old la Port e Ramp La P o r t e State Hwy 2 2 5 State H w y 1 4 6 Hi g h w a y 1 4 6 14 t h Plainbrook 10 t h St a t e H w y 1 4 6 Dr i v e w a y State Hwy 22 5 State Hwy 225 Al l e y Al l e y Madison Avenue D 8t h Tyler Al l e y Sunset Ridge F101-03-00 F101-06-00 F101-01-00 F1 0 1 - 0 0 - 9 9 F216-00-00 F1 0 1 - 0 8 - 0 0 F210-00-00 F1 0 1 - 0 7 - 0 0 F2 1 2 - 0 0 - 0 0 F1 0 1 - 0 6 - 0 2 F1 0 1 - 0 6 - 0 3 ³ 01,000500Feet EXHIBIT1 CITY OF LA PORTEBATTLEGROUND ESTATESPHASE 1 PELIMINARY ENGINEERING REPORT KLOTZ PROJ. NO.: 0127.014.000 SCALE: DATE: NOVEMBER 4, 2011 (Aerial Source: HGAC 2010) 1 " = 1,000 ' Legend Battleground Estates Study Stream Streets Avenue P Pa t h : J : \ 0 1 2 7 . 0 1 4 . 0 0 0 \ 0 7 . 0 0 C A D D \ G I S \ E x h i b i t s \ E x h i b i t 1 - P r o j e c t L o c a t i o n M a p . m x d Project Location:Replace 2-42" CMP culvertswith 2- 8'x10' RCB PROJECT LOCATION &AERIAL MAP F101-00-00 F1 0 1 - 0 8 - 0 0 22 20 8 6 4 24 2 18 16 14 12 10 26 28 30 32 34 3638 44 42 40 46 48 50 52 54 5658 24 20 22 22 46 26 26 26 26 24 20 48 20 28 18 26 2628 22 26 26 30 24 18 2 4 28 22 2 224 24 24 20 16 22 24 20 28 20 22 24 22 22 18 26 24 24 18 24 24 26 2 2 26 28 La Porte LSe n s 16 t h 1 0 t h 12 t h Avenue L Avenue P State Hw y 2 2 5 Avenue H E H St a t e H w y 1 4 6 I 14 t h 8t h Tyler 11 t h 1s t 4t h 5t h 6t h 13 t h Ro b i n s o n 26 t h Houston 3r d Al l e y Barbours Cut Hig h w a y 1 4 6 Madison Viola 7t h Old la Port e D Unnamed S t r e e t 9t h Br o a d w a y Al v y S t a t e H w y 1 4 6 S e r v i c e Bois D Arc Deaf Smith San Jacinto Lovinnie Le m o n Va l l e y V i e w Old Strand Mi s s i o n Avenue D 2n d St r a n g Monument La u r a Ash Pine Bexar Cavalry Ea s y Sh i r l e y Cannon Elm Fieldcrest Lo m a x Sa n t a A n n a Alamo Plainbrook Flintlock Dr i v e w a y El m w o o d Oak Ba t t l e v i e w PeachSunset Ridge Elizabeth Mil l e r C u t O f f Milam Du a n e Bowie Pa r k i n g L o t Po s t T r a i l e r P a r k Ramp Bu c h a n a n Tr a v i s Fairlane Sky View Bay View South P Old la Port e Tyler 10 t h Avenue D Al l e y Sunset Ridge State Hwy 225 Fieldcrest Ho u s t o n Al l e y Avenue P H La P o r t e Dr i v e w a y St a t e H w y 1 4 6 Ramp Hi g h w a y 1 4 6 Al l e y Plainbrook La Porte State Hwy 2 2 5 14 t h 8t h E Br o a d w a y State H w y 1 4 6 26 t h F101-03-00 F101-06-00 F101-01-00 F1 0 1 - 0 0 - 9 9 F216-00-00 F1 0 1 - 0 8 - 0 0 F210-00-00 F1 0 1 - 0 7 - 0 0 F2 1 2 - 0 0 - 0 0 F1 0 1 - 0 6 - 0 2 F1 0 1 - 0 6 - 0 3 ³ 01,000500Feet EXHIBIT2 CITY OF LA PORTEBATTLEGROUND ESTATESPHASE 1 PELIMINARY ENGINEERING REPORT TOPOGRAPHIC MAP KLOTZ PROJ. NO.: 0127.014.000 SCALE: DATE: NOVEMBER 4, 2011 (Aerial Source: HGAC 2010) 1 " = 1,000 ' Legend Contour Battleground Estates Study Stream Streets Avenue P Pa t h : J : \ 0 1 2 7 . 0 1 4 . 0 0 0 \ 0 7 . 0 0 C A D D \ G I S \ E x h i b i t s \ E x h i b i t 2 - T o p o g r a p h i c M a p . m x d &; DA22183-ac&; DA0597-ac &; DA1595-ac&; DA1194-ac &; DA1392-ac &; DA0191-ac &; DA0881-ac &; DA1067-ac &; DA1867-ac &; DA1963-ac &; DA1461-ac &; DA0961-ac &; DA0358-ac &; DA0758-ac &; DA0666-ac &; DA2049-ac &; DA0438-ac &; DA1626-ac &; DA1220-ac &; DA0219-ac &; DA2118-ac &; DA1712-ac G B E 16 t h La Porte Spencer 8t h 1s t 4t h 6t h 5t h 3r d 7t h Se n s A Avenue L 2n d Avenue P 10 t h State Hwy 2 2 5 L F 11 t h Park Avenue H St a t e H w y 1 4 6 12 t h Un d e r w o o d Ut a h 9t h Io w a Main C L o b i t Polk 15 t h Barbours Cut K a n s a s H I 14 t h Vi r g i n i a Id a h o Catlett Tyler Birch C a r r o l l H o l m e s Carlow N u g e n t Adams Rustic Gate Ca n a d a Hw y 1 4 6 Dr i f t w o o d Fa r r i n g t o n Ro b i n s o n St a t e H w y 1 4 6 D 26 t h Mesquite Houston Br o a d w a y R o s e b e r r y Bay s h o r e 13th W i l l m o n t Fl e e t w o o d 23 r d Ba y e r Dogwood Hig h w a y 1 4 6 Madison Lo m a x S c h o o l O h i o Rustic Rock Andr i c k s Ce d a r m o n t Viola Crestway Old la Port e Collingswood Dover Hill D Unnamed S t r e e t Wren Creekview Sta t e H w y 1 3 4 Glenvalley Parkcrest My r t l e C r e e k Al v y Ston e m o n t Bois D Arc Winding Trail Te x a s Robin Antrim Glenpark 17 t h S a n J a c i n t o 18 t h Spruce Lovinnie Le m o n Belfast Be r n a r d Mulberry Montgomery Moore Old Strand M o n t a n a Avenue D Hills d a l e Ma r y Ramp Me a d o w L a r k Quiet Hill Cardinal La u r a Ash Cl a r k s v i l l e Lee Ol d U n d e r w o o d Br o w n i n g Ta n y a V a l l e y B r o o k Old Orchard Pine Alley Pinewood Ba y o u G l e n Bexar Cavalry Ca m m y Ea s y Ar i z o n a Cany o n S p r i n g s Sh i r l e y Fieldcrest Eag l e N e s t 24 t h 25 t h Ga u c h o Je s s i c a Willo w C r e e k Plainbrook Sioux Cap l a n Dr i v e w a y Park w a y Wa y s i d e Lo c L o m a Cr a n d a l l Co u p l a n d Blac k w e l l O t t e r C r e e k De s e r t R u n Springwood Br o w n e l l Mil l e r C u t O f f Oak G r o v e Du a n e Pecan Brookside B A r e a McCarty R i v e r C r e e k Bu c h a n a n St a t e H w y 1 4 6 N o r t h Barton P Fairlane Rosc o e Ramp 13 t h D H La Porte Al l e y 14 t h 14 t h Al l e y 13 t h F 8t h H D 14 t h I Sp e n c e r Al l e yCarlow D Alley 11 t h Rustic Gate Alley D Tyler 17 t h Ol d U n d e r w o o d 12 t h Un n a m e d S t r e e t Ramp State Hwy 2 2 5 F O h i o La Porte E 13 t h State Hwy 225 B State Hwy 2 2 5 State H w y 1 4 6 G H Driveway C 12 t h D La Porte Lo m a x S c h o o l 26 t h Hi g h w a y 1 4 6 Catlett E C I Bl a c k w e l l La Po r t e Collingswoo d La P o r t e Se n s I Polk Alley C F E A B E I 9t h D H Avenue P Driveway ³ 02,0001,000 Feet EXHIBIT3 DRAINAGE AREA MAP CITY OF LA PORTEBATTLEGROUND ESTATESPHASE 1 PELIMINARY ENGINEERING REPORT KLOTZ PROJ. NO.: 0127.014.000 SCALE: DATE: NOVEMBER 4, 2011 (Aerial Source: Landiscor 2010) 1 " = 2,000 ' Legend Battleground Estates Streams Drainage Area Pa t h : J : \ 0 1 2 7 . 0 1 4 . 0 0 0 \ 0 7 . 0 0 C A D D \ G I S \ E x h i b i t s \ E x h i b i t 3 - D r a i n a g e A r e a M a p . m x d F101-00-00 F1 0 1 - 0 8 - 0 0 12 6 9 0 . 4 92 6 6 . 4 1 5 11542.80611592.80711752.808 29 4 9 . 3 9 1 4 28 9 6 . 7 9 3 5 56 6 9 . 6 8 9 9 32 7 6 . 9 7 6 6 33 2 3 . 4 4 9 5 56 1 9 . 6 7 5 3 696 7 . 9 4 6 3 13 6 6 3 . 8 7 8 87 1 2 . 9 8 5 4 1247.4758 86 6 3 . 0 0 5 9 48 1 9 . 4 0 9 2 60 9 8 . 9 2 1 4 40 1 9 . 3 8 3 1 12 8 7 4 . 6 0 6 12 5 1 8 . 0 0 1 1756.8397 7761 . 7 4 2 7 24 6 9 . 3 9 9 2 63. 6 2 3 4 9 7 1297.5189 85 6 7 . 9 9 2 2 15160.244 14 5 3 4 . 3 8 6 10 0 6 6 . 4 4 6 61 8 9 . 1 1 0 4 1016.6597 63 2 8 . 3 8 1 3 11313.7 1 5 10860.5 0 9 La Porte L Se n s 16 t h 12 t h 1 0 t h Avenue L Avenue P State Hwy 2 2 5 Avenue H E H I 14 t h St a t e H w y 1 4 6 8t h 11 t h 13 t h Ro b i n s o n 1s t 26 t h 4t h 5t h Houston 6t h Barbours Cut Hig h w a y 1 4 6 Madison Viola Old la Port e Al l e y Unnamed S t r e e t 9t h Al v y St a t e H w y 1 4 6 S e r v i c e Bois D Arc Deaf Smith 3r d San Jacinto Lovinnie Le m o n Br o a d w a y Va l l e y V i e w Old Strand Mi s s i o n St r a n g Monument La u r a Ash 7t h Pine Bexar Cavalry Ea s y Sh i r l e y Cannon Elm Fieldcrest Lo m a x Sa n t a A n n a Alamo Plainbrook Dr i v e w a y El m w o o d Oak Sunset RidgeElizabeth Mi l l e r C u t O f f Milam Du a n e Ba t t l e v i e w Bowie Parking Lot Po s t T r a i l e r P a r k 2n d Ramp Bu c h a n a n St a t e H w y 1 4 6 N o r t h Tr a v i s Fairlane Sky View Bay View P Ramp Pa r k i n g L o t Madison H E Avenue P State Hwy 225 Madison La Porte Plainbrook 14 t h La P o r t e 26 t h 8t h Hi g h w a y 1 4 6 Br o a d w a y State H w y 1 4 6 State Hwy 225 Old la Port e St a t e H w y 1 4 6 Ho u s t o n State Hwy 2 2 5 Dr i v e w a y ³ EXHIBIT4 HEC-RASCROSS-SECTION LOCATION MAP CITY OF LA PORTEBATTLEGROUND ESTATESPHASE 1 PELIMINARY ENGINEERING REPORT KLOTZ PROJ. NO.: 0127.014.000 SCALE: DATE: NOVEMBER 4, 2011 (Aerial Source: Landiscor 2010) 1 " = 1,000 ' Legend Battleground Estates Study Stream Cross-Section Pa t h : J : \ 0 1 2 7 . 0 1 4 . 0 0 0 \ 0 7 . 0 0 C A D D \ G I S \ E x h i b i t s \ E x h i b i t 4 - C r o s s - S e c t i o n L o c a t i o n M a p . m x d 01,000500Feet APPENDIX A PHOTOS Photo 1 Sediment on the outfall apron of 8'x10' culverts atF101-00-00 and Avenue P Photo 2 Sediment in the bottom of the 8'x10' RCBs serving F101-00-00 at Avenue P Photo 3 Upstream of structure at Avenue P (2 - 42" CMPs) Photo 4 Channel upstream of composite structure serving F101-00-00 at Avenue P Photo 5 Channel downstream of composite structure serving F101-00-00 at Avenue P FIGURES 11 0 0 0 12 0 0 0 13 0 0 0 14 0 0 0 1500016000 05101520 F1 0 1 - 0 0 - 0 0 _ 2 P l a n : E x i s t 2 1 1 / 1 5 / 2 0 1 1 E x i s t i n g C o n d i t i o n s Ma i n C h a n n e l D i s t a n c e ( f t ) Elevation (ft) Legend WS 100-yr (1%)WS 50-yr (2%)WS 10-yr (10%)Ground LOB ROB F1 0 1 - 0 0 - 0 0 M a i n C h a n n e l 12 0 0 0 13 0 0 0 14 0 0 0 1500016000 05101520 F1 0 1 - 0 0 - 0 0 _ P r o p 2 P l a n : P r o p o s e d 2 1 1 / 1 5 / 2 0 1 1 P r o p o s e d C o n d i t i o n s Ma i n C h a n n e l D i s t a n c e ( f t ) Elevation (ft) Legend WS 100-yr (1%)WS 50-yr (2%)WS 10-yr (10%)Ground LOB ROB F1 0 1 - 0 0 - 0 0 M a i n C h a n n e l