th dams. below the distribution pipe (Figure 6.20). Dams should not be placed where a hole in the lateral will be. These dams help even out the hydraulic load on the trenches. Add gravel to the trenches up to the level of the distribution pipes. Don't put gravel into the manifold trench by mistake. Check for level gravel surfaces. Next, place the system pieces into their respective trenches, check hole and turn-up alignment, and glue the whole works together. The last connection should be the supply pipe to the dosing cham- ber. Remember to include the 0.25-in. antisiphon hole, if it is needed. Backfill the supply and manifold trenches, and place the required gravel in the lateral trenches. Place the barrier material CONVENTIONAL SYSTEM MODIFICATIONS (straw, untreated building paper, etc.) on the surface of the gravel. Backfill the lateral trenches. Finally, cut the turn-up ends to the length you want, add an adapter, and attach a screw cap. If they don't stick very far out of the ground, you may wish to protect the turn-ups from lawn mowers by placing lengths of 4- to 6-in. diam- eter PVC or clay pipe over them. After all the hydraulic and electrical connections are made, the system should be checked to see if it works properly. Take off the screw cap on the end of the uphill lateral and attach a 4-ft length of clear plastic hose. Fill the dosing chamber with water to a level above the high water alarm and turn on the electricity. The alarm should go off and after water is pumped to the distribution system, water should run up into the plastic hose. With the pressure adjust- ment valve, adjust the pressure until the water level in the hose is at the design level above the plane of the lateral. Make sure that the alarm stopped and that when the pump shut itself off it was still submerged. Replace the end cap. Operation and Maintenance Plant some grass or other shallow-rooted vegetation over the lat- eral lines if you don't plan to garden the area. Root crops should not be irrigated with effluent. Any cut in the s