Laserfiche WebLink
r <br /> D-35 <br /> Part 3: Gravelless Options <br /> for Trench Systems <br /> The Gravelless Trench has been used in Texas since 1971. It is an <br /> extremely viable option for onsite sewage treatment in Minnesota, <br /> and testing and data show that it is as reliable as a trench filled with <br /> gravel. As a result, it has been adopted as a standard system for use <br /> in Minnesota. (See Figure D-33.) <br /> The idea of using something other than rock to hold the trenches apart <br /> is not new. Chapter 7080 currently recognizes two acceptable options. <br /> The first is gravelless pipe, which is corrugated pipe surrounded by a <br /> synthetic fabric. The second is a chamber made out of a nondegradable <br /> material, typically plastic, used to hold the soil apart. <br /> GRAVELLESS TRENCH CONSTRUCTION DETAILS <br /> 1 1/2" Inspection <br /> Inlet Pipe to Next Well <br /> Drop Box 1 1/2 Male 0 <br /> Adapter <br /> a`I• <br /> — 12" Soil Backlill <br /> ) <br /> : <br /> \\� _1 • • • e • • •0 • <br /> Corrugated Tubing Covered • <br /> nnnnnrvnnnr with Geotextile FabriChnnnnrnnnr, <br /> Drop Box 1.1 <br /> Trench Length = up to 100 Feet <br /> Overfill to Allow <br /> NOTES: 1. Bottom of trench must be level. Top <br /> for Settling of tubing must be level. <br /> V Soil Te <br /> i`\\\G 12" of Soil 2. Scarily trench bottom and sidewalls <br /> Backfill Backfill at least 12 inches above trench bottom <br /> 24" <br /> to expose natural soil. <br /> I <br /> A. 11" <br /> UI <br /> 2_L 3. For proprietary products consult <br /> manufacturers performance criteria. <br /> 1.1 Holes Located <br /> 24" ' at 4 and <br /> 8 O'Clock <br /> Figure D-33 <br />