Urban Water Management Plan 2015

minimum historical yields for a running average of three years. The period between 2013 and 2015 was selected to represent the multiple dry years. The percent of average supply for the third multiple-dry year does not include additional water transfers that may be obtained by SCVWD during extreme droughts for the Llagas subbasin.

Table 7-1 Basis of Water Data

Volume Available

Percent of Average Supply

Base Year

Year Type

(AF)

(%)

Average Year

63,900

100%

Single-Dry Year

1977

60,705

95%

Multiple-Dry Years 1st Year

2013

60,705

95%

Multiple-Dry Years 2nd Year

2014

54,315

85%

Multiple-Dry Years 3rd Year

2015

41,535

65%

Notes: 1. Available volume for single dry and multiple dry year periods based on estimated percent of average supply, per SCVWD 2015 UWMP.

7.2.2 Sources for Water Data To establish a basis of normal, single dry, and multiple dry hydrologic water year’s, historical rainfall data available from DWR was analyzed, as it relates to the City. 7.3 SUPPLY AND DEMAND ASSESEMENT Law 10635 (a) Every urban water supplier shall include, as part of its urban water management plan, an assessment of the reliability of its water service to its customers during normal, dry, and multiple dry water years. This water supply and demand assessment shall compare the total water supply sources available to the water supplier with the total projected water use over the next 20 years, in five-year increments, for a normal water year, a single dry water year, and multiple dry water years. The water service reliability assessment shall be based upon the information compiled pursuant to Section 10631, including available data from state, regional or local agency population projections within the service area of the urban water supplier.

During prolonged years of drought, City-wide water use patterns are expected to change. Typically, outdoor water use will initially increase as irrigation is used to offset decreased rainfall.

August 2016

7-3

City of Morgan Hill 2015 Urban Water Management Plan