Pipe should be sized so that the flow velocity should not exceed five (5) feet per second (fps). In exceptional cases, it might be permissible to go to 5.5 fps velocity, but that should be for a short line (less than 1000 feet) with adequate air relief, pressure relief and vacuum relief valves.

• The system should be designed to provide adequate pressure to break up the waste water and give uniform distribution of the effluent. The pressure required will depend on the particular sprinkler and model number, but in no case should it be less than 50 psi. There are some low pressure gun sprinklers, but most gun sprinklers need 70-90 psi at the nozzle tip.

• Both tapered bore and ring orifice gun nozzles can be used. The tapered bore nozzle tends to give a larger diameter of coverage at the same flow rate and pressure than a ring orifice.

• With traveling gun sprinklers, hydrant spacing is normally 70-80% of sprinkler diameter (75% is a good range for design).

• If gun sprinklers are used on dry hydrants, hydrant spacing (both in the lateral line direction and between lateral lines) should not exceed 60% of effective sprinkler diameter based on manufacturers' literature (gun operating pressure at the most distant location from the pump or at the highest elevation, whichever is lowest). In operating the system, two adjacent sprinklers should never be operated at one time. This should reduce the potential for runoff.

• Any gun sprinkler, whether stationary or traveler, should be operated when wind speed is at a minimum (five (5) miles per hour or less).

• Traveling gun sprinklers can be operated where the gun is operated in a part circle or full circle mode. When the gun is operated part circle, the application rate is increased, which increases the potential for runoff. As an example, if a gun is operated half circle, the application rate is doubled. For most guns operated full circle, the overall application rate is 0.30 inch per hour or greater, and there are parts of the circle where the application rate can double.

• When operating a land application system, the maximum effluent applied at one time should not exceed one inch (0.5 to 0.75 inch is preferable).

When applying for cost share a grower should submit the following information:

• field dimensions
• • field slope (average and maximum slope, show direction of the slope)
• • crop to be plante
• • watercourse, drinking water well, residence, property boundary, road, etc., next to the field
• •location of the lagoon
• • distance from the lagoon to field
• • maximum elevation difference from lagoon to highest point in the field
• • sprinkler make, model number and nozzle size along with sprinkler performance chart from the manufacturer
• • pump make, model number and engine or motor horsepower along with a pump curve from the manufacturer
• • traveler make and modelnumber and hose size and length alongwithdescriptive literature from the manufacturer
• • applicant should indicate whether sprinlcler or traveler will be operated in a part circle or full- circle mode

• Based on adequate data submittedby the applicant and checked by the USDA-Soil Conservation Service District Conservationist (DC), the DC should be able to design a system that is best suited. Remember that the theory behind land application is to uniformly apply the wastewater at agronomic rates without runoff from the site.

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