SPEC WRITER NOTE: The following paragraphs are provided for design direction of the system. Delete Appendix I and Appendix II from this section and design the project system to meet the site conditions. APPENDIX I – ALLOWABLE SITE CHARACTERISTICS FOR CONCRETE SHALLOW TRENCH APPLICATION ALLOWABLE SITE CHARACTERISTICS FOR CONCRETE SHALLOW TRENCH APPLICATION (SEE NOTE 1) SITE CONDITION GENERAL CONDITIONS OF SURFACE WATER TRENCH GROUND WATER DURING THE ACCUMULATION CONSTRUCTION WETTEST PERIOD OF THE RAINFALL/ YEAR IRRIGATION A. Fine Water table generally 300 5 years - 7 day Continuous wall grained mm (1 foot) below lowest rainfall equal and bottom. impervious point of water entry (See to or less than or semi Note 5) with not more 250 mm (10 inches). (See pervious than 25% of the length of Note 2) and coarse the proposed concrete grained trench system showing impervious water within 300 mm (1 foot) of the lowest point of water entry. B. Coarse Same as for A. above. 5 years - 7 day Same as for A. grained rainfall equal above semi to or less than pervious 250 mm (10 and inches). pervious (See Note 2) Water table generally 600 5 years - 7 day Continuous wall; mm (2 feet) or more below rainfall equal openings may be point of water entry with to or less than provided in not more than 10% of the 200 mm (8 trench bottom to length of trench system inches). (See provide drainage. Note 2) showing water within 600 mm (2 feet) but not closer than 300 mm (1 foot) to lowest point of water entry. C. Swelling Same as for A. above. Same as for A. Same as for A. soils (See above. above plus design Note 3) of joint spacing and joint details to accommodate movement.
SPEC WRITER NOTE: The following paragraphs are provided for design direction of the system. Delete Appendix I and Appendix II from this section and design the project system to meet the site conditions. APPENDIX I – ALLOWABLE SITE CHARACTERISTICS FOR CONCRETE SHALLOW TRENCH APPLICATION ALLOWABLE SITE CHARACTERISTICS FOR CONCRETE SHALLOW TRENCH APPLICATION (SEE NOTE 1) SITE CONDITION GENERAL CONDITIONS OF GROUND WATER DURING THE WETTEST PERIOD OF THE YEAR SURFACE WATER ACCUMULATION RAINFALL/ IRRIGATION TRENCH CONSTRUCTION A. Fine grained impervious or semi pervious and coarse grained impervious Water table generally 300 mm (1 foot) below lowest point of water entry (See Note 5) with not more than 25% of the length of the proposed concrete trench system showing water within 300 mm (1 foot) of the lowest point of water entry. 5 years - 7 day rainfall equal to or less than 250 mm (10 inches). (See Note 2) Continuous wall and bottom. B. Coarse grained semi pervious and pervious (See Note 2) Same as for A. above. 5 years - 7 day rainfall equal to or less than 250 mm (10 inches). Same as for A. above Water table generally 600 mm (2 feet) or more below point of water entry with not more than 10% of the length of trench system showing water within 600 mm (2 feet) but not closer than 300 mm (1 foot) to lowest point of water entry. 5 years - 7 day rainfall equal to or less than 200 mm (8 inches). (See Note 2) Continuous wall; openings may be provided in trench bottom to provide drainage. C. Swelling soils (See Note 3) Same as for A. above. Same as for A. above. Same as for A. above plus design of joint spacing and joint details to accommodate movement.
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