Del Norte System Improvements Applic

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'\ Standard guidelines indicate that water pipeline pressures in the range of 30 to 90 p.s.i. under conditions of maximum daily water use are acceptable. Results from Analysis Condition 1 conform to these guidelines with the exception of:l::3 nodes indicating pressures slightly above 90 p.s.i. and at nodes representing water storage tanks. Distribution system areas that experience the higher pressures certainly do not experience a lack of water supply, but occasionally hot water tank pressure relief valves will open. Also, pipeline leakage and water usage is often excessive. The very low pressures at the tank nodes simply reflect the depth of water in the tank and should not be used in determining pipeline adequacy. I I As previously mentioned, ISO guidelines indicate that pipeline water pressures should not be less than 20 p.s.i. during fire hydrant use. Analysis Condition 2 indicates a pressure of :1::12 p.s.i. at node 109 where the 750 g.p.m. fire flow is simulated. This is an undesirable condition. Analysis Conditions 3 and 5 both correct the undesirable pressure at node 109. Analysis Condition 4 does not improve the undesirable pressure at node 109. IV. WATER SUPPLY IMPROVEMENT AL TERNA TIVES A. General There are two general changes that will result in an improvement in available water supply for the Town of Del Norte. These changes fit into the following two broad categories: 1) Reduction in water use; 2) increasing water supply volume. Subsequent paragraphs address alternatives that are specific to Del Norte's situation. B. Reduction in Water Use Water Pressure In other municipalities, lowering distribution water pressure by 20 p.s.i. has resulted in as much as 30% reduction in water consumption. Water pressures in most areas of Del Norte range from :1::50 to :1::85 p.s.i. Most household appliances that use water are designed to operate at pressures as low as 20 p.s.i., however the most desirable pressure is 30-50 p.s.i. Minimum required water pressure to provide fire protection is 20 p.s.i., but to obtain adequate flows from fire hydrants, the water pressure usually needs to be :1::30 p.s.i. As previously described, the Town's distribution system includes two pressure zones. The zone supplying the southern portion of town is pressurized by the water in the upper tank. Water users within this portion of town are located at a higher elevation than the remaining municipal users. The water pressure in the remaining portion of the town is controlled by the elevation of water in the lower reservoir and the well pumps supplying water to the distribution system and lower reservOIr. 12