06-19-2003 Regular Meeting and Public Hearing of the La Porte Planning and Zoning Commission

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• • Tsble 3.4 PROTECTION REQUIREMENTS AT WATER LINE -FORCE MAIN CROSSINGS PROPOSED WATER PRIMARY PROPOSED WATER PROPOSED FORCE MAIN CONDITION EXISTING FORCE MAIN ~ OR EXISTING WATER PROPOSED FORCE MAIN SECONDARY WATER OVER WATER UNDER WATER OVER WATER UNDER CONDITIONS FORCE MAIN FORCE MAIN FORCE MAIN FORCE MAIN Less Greater Less Greater Less Greater Less Greater 1F THE than 2' than 2' than 2' than 2' than 2' than 2' than 2' than 2' CLEARANCE IS ~ but less but less but less but less than 10' than 10' than 10' than 10' *Protection 1 2 . 3 4a or 4b 5 6a 3 6a & 6b R ent *PROTECTION REOU)REMENTS FOR FORCE MAIN CROSSINGS (All clearances shall be measured from outside wall to outside wall) 1. Construct waterline with a 20-foot steel section with all related appurtenances centered above the force main; 6-inch minimum clearance. 2. Construct water line with one 20 foot joint of C-900, C-905 PVC centered above the force main. 3. Not allowed 4. a Auger, bore & jack or microtunne! 10 feet minimum each side of force main. Place one 20-foot joint of C-900 or C90S, 1 SO psi, centered under sanitary sewer. Fill bore hole with bentonite%lay mixture or grout; 2 foot minimum clearance. b. OR replace the existing force main with ISO psi lined ductile iron pipe with appropriate adapters on all portions of the force main within 10 feet of the water line. S. Center a minimum 18 foot joint of force main, ISO psi lined ductile iron pipe under water line and use cement-stabilized sand bac~ll for all portions of the force main with 10 feet of the water line as measured perpendicularly from arty point on the water pipe to the wastewater pipe (minimum 2.5 sacks cement per cubic yard of sand). The cement-stabilized sand bedding shall start at a point 6 inches below the bottom of the sanitary sewer to 6 inches above the top of the sanitary sewer and one quarter of the pipe diameter on either side of the force main. 6. ~ Minimum 18 foot of sanitary sewer force main, 1 SO psi lined ductile iron pipe centered at the water line. 3. Sanitary Sewer Manholes: Provide a minimum 10 foot horizontal clearance from outside wall of existing or proposed manholes, make manholes and connecting sewers watertight and test for leakage. If a 10 foot clearance caimot be obtained, the water line may be located closer to the manhole when prior approval has been obtained from the Planning Department by using one of the procedures below; however, in no case shall the clearance be less than 4 feet. a. Water line may be encased in a carrier pipe. ~ Encasement shall be steel water line in a steel carrier pipe. b. The water line may be augured, bore &jacked, or microtunneled past the manhole with at least one 20 foot section of C-900 PVC pipe, 150 psi, installed centered about the existing sanitary manhole with .pressure grouting using a bentonite%lay mixture or other commercial grouts. Water System Design Criteria Page 11 of 12