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TABLE 3 The amount of water needed is determined by the COUNTY ORDINANCES IN CALIFORNIA intended use of the water. For example, on the average WITH COUNTY ORDINANCES TED APPLICATION TO WELLS each person in a household uses 100 gallons (380 litres] of (As of December ON T water a day. To the daily household use must be added seasonal uses such as lawn and garden irrigation, swimming pools, etc. Table 4 lists the volume of water supplied from a small capacity well, assuming continuous pumping for Ordinance Date 24 hours. Thus a well supplying one to three gallons County Number Adopted Application (4 to 11 litres] per-minute is a reasonable amount for a single family dwelling. Additional amounts, such as for Kern G1225 12/16/69 Community water supply watering livestock or irrigating small acreages of crops, wells must be added to these values. Table 4 also indicates that a 1 9/21/81 Agricultural wells family of four could subsist on the water supplied by a well G332 Domestic water supply pumping constantly at the rate of only one-quarter gallon lKarin G332 9/21 146 196 0.95 litre) per minute. Unfortunately, at this rate there Plumas 5/73 Domestic wells only Riverside 340A 5/3/48 1 Provisions concern permit is little margin for error. San Francisco 659 1952 Individual domestic wells Small Capacity Wells. Performance tests for small only capacity wells are relatively simple. A widely used test for Sierra 420 5/7/74 Well construction only small capacity wells is a pump test which lasts for four hours or until an apparently stable pumping level has been achieved at a rate equal to that expected for the permanent pump. However, in the hilly and mountainous "hard rock" Amended December 1,•1952 and December 23, 1957. areas of the State there are no defined aquifers and supplies are related to fracture patterns, the nature and extent of the soil mantle, faults, changes in stratigraphy, etc. In Design and Performance Guidelines such areas the production potential of a well cannot be accurately assessed. Further, wells in these areas often While the standards presented here (see Chapter II exhibit a satisfactory initial production, which then following) are designed to protect the continued utility of declines due to poor recharge characteristics of the surround- the State's ground water resources, they are only incidently ing material. In such situations a longer than usual test, related to the effective use of these resources. Events of upwards of 12 to 24 hours (and longer) duration, may be the past decade have emphasized the need for conservation of desirable. water and energy. Furthermore, consumers (in this case, well owners) have become more aware of problems resulting from Bailing or air-blow tests give an approximate inefficient operation (as reflected in increased energy indication of production. They do not provide information of consumption) and inadequate maintenance. the accuracy needed to determine well capacity or to design an efficient pump system. (Air lift testing differs from Accordingly, this section was prepared to provide air-blow testing. It involves pumping with air, not blowing well owners and drillers with guidelines for measuring the water out of the well as is the case with the air-blow performance that will lead to the design and construction of test.) more efficient wells as well as those requiring less maintenance. The ability of the water level in a small capacity well to recover should be observed. If the water level fails Testing for Capacity to return to nearly its original level after 24-hours, the reliability of the producing zone is open to question. Every well owner is interested in how much water Large Capacity Wells. Where large capacity wells the well will produce and how dependable the production will are concerned, capacity tests are more elaborate and be with time. To make that determination a capacity test or extensive. Such wells are usually located in defined, performance test.must'be made. Usually this involves install- productive ground water basins, where considerable informa- ing a pump and operating it at the expected production rate tion on existing conditions is normally available to aid in over a certain length of time. - There is considerable varia- the evaluation of their performance. All should be pump tion in actual practice on how such tests are performed tested; bailer tests are -of little value. The test pump depending on the dimensions of the well, including expected should be capable of pumping 125 percent of the desired yield capacity and intended use as well as geologic conditions at of the well. Pumping should be continued at a uniform rate the site. Obviously, for a small capacity well, i.e., one until the "cone of depression" reflects any boundary that produces under 50 gallons (190 litres) per minute, the condition that could affect the performance of the well. test would not be as elaborate as it would be for a high This could be as short as six hours and as long as several capacity well but is no less important. days, depending on aquifer characteristics and knowledge