ANNUAL INVENTORY of WATER USE LAKE TAHOE & TRUCKEE RIVER BASINS Calendar Year 2016
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STATE OF CALIFORNIA DEPARTMENT OF WATER RESOURCES ANNUAL INVENTORY OF WATER USE LAKE TAHOE & TRUCKEE RIVER BASINS Calendar Year 2016 This page intentionally left blank STATE OF CALIFORNIA Edmund G. Brown, Jr., Governor CALIFORNIA NATURAL RESOURCES AGENCY John Laird, Secretary for Natural Resources Department of Water Resources Grant Davis Director Cindy Messer Chief Deputy Director Eric Koch, Deputy Director (Acting) Integrated Water Management Arthur Hinojosa, Chief Division of Integrated Regional Water Management Gary Lippner, Chief North Central Region Office ANNUAL INVENTORY OF WATER USE LAKE TAHOE & TRUCKEE RIVER BASINS Calendar Year 2016 Preparation Team California Department of Water Resources North Central Region Office Regional Planning and Coordination Branch California – Nevada & Watershed Assessment Section: Gary Lippner, P.E, Office Chief Amardeep Singh, P.E., Branch Chief Paul R. Larson, P.E., Section Chief Tom Scott, Engineer, W.R. David Willoughby, Engineer, W.R. Office of the Chief Counsel: Linda Ackley, Senior Attorney Executive Summary The Lake Tahoe and Truckee River watershed basins are shared between the states of California and Nevada. This annual inventory of water use reports the quantity of water used from surface water and groundwater sources within the California portion of these two watershed basins during the calendar year of record, 2016. This report is compiled annually and submitted to the Truckee River Operating Agreement (TROA) Administrator to comply with the interstate water allocation requirements of Public Law (PL) 101-618, Section 204(d), and further defined in TROA. This 2016 Annual Inventory of Water Use report is the first such annual report produced since implementation of TROA in December 2015. Also included in this report is an estimation of the total amount of water depleted from California’s Truckee River Basin in accordance with the depletion calculation requirements defined in TROA. Depletion refers to the amount of water that is used or consumed, but is not ultimately replenished into the watershed’s streams or groundwater aquifers through percolation, treatment, etc. The maximum depletion criteria defined in TROA only applies to water used in the Truckee River Basin. The primary source of potable water within the Lake Tahoe and Truckee River basins is from groundwater. While the public water purveyors supplying the communities of Kings Beach, Tahoe City, Tahoma, Homewood, South Lake Tahoe, and the Town of Truckee are the largest significant users or distributers of water within the basins, this report also quantifies the amount of water used by private single family dwellings, multi-family and commercial developments, golf courses, and other public agencies serving smaller developments or local amenities, including campgrounds, trailer parks, and small shared community systems. The quantity of water used for snowmaking is also reported in accordance with PL 101-618 and TROA. California’s total annual allocation from surface and groundwater sources within the Lake Tahoe Basin is 23,000 acre-feet. The total annual allocation from Truckee River Basin sources for use in California is 32,000 acre-feet, of which no more than 10,000 acre-feet can be from surface water sources. Additionally, the calculated annual depletion within the Truckee River Basin must not exceed 17,600 acre-feet as determined by depletion calculations prescribed in TROA. These allocations were originally determined by the California-Nevada Interstate Compact Commission and ratified by California and Nevada in 1970 and 1971, respectively, but were never formally approved by the United States Congress. In 1990, PL 101-618 was passed by Congress and signed by the president; however, it required that certain conditions be satisfied prior to the California-Nevada interstate allocation mandate becoming effective. The final condition was satisfied 25 years later with the official implementation of TROA in December 2015, thereby effectively establishing the interstate allocation and the reporting requirements described above. Total Reportable Water Use for 2016: The total reportable quantity of water used by California interests from the Lake Tahoe Basin in Calendar Year 2016 totaled 11,950 acre-feet, the equivalent of 52 percent of the allocation of 23,000 acre-feet. The total reportable water used by California interests from the Truckee River Basin for Calendar Year 2016 totaled 8095 acre-feet, or the equivalent of 25 percent of the allocation of 32,000 acre- feet. Of this total, 310 acre-feet was reported to be diverted directly from surface water sources, or 3 percent of the allowable maximum limit of 10,000 acre-feet. The total reportable water usage within the Lake Tahoe and Truckee River 1 basins by California interests for Calendar Year 2016 is summarized in Table 1, below, and further described throughout this report. Table 1 Summary of California’s 2016 Reportable Water Use for the Lake Tahoe and Truckee River Basins Lake Tahoe Basin Truckee River Basin (acre-feet) Manner of Use (acre-feet) Total Water Use Surface Portion Municipal & Industrial (Includes 11,450 6090 230 private domestic wells) Golf Course Irrigation 500 1,920 80 Snowmaking 0 85 - Total Reportable 11,950 8,095 310 Water Use for 2016 Up to 10,000 Total Annual California Allocation 32,000 maximum from 23,000 per PL 101-618 (Total Water Use) surface water sources % of Total Annual 52% 25% California Allocation Total Truckee River Depletion for 2016: Based on the water usage data provided and other applicable data, either reported or estimated, the total Truckee River depletion for 2016 was calculated to be 2,810 acre-feet, or the equivalent of 16 percent of the allowable annual depletion of 17,600 acre-feet. The Truckee River total annual depletion calculation process is described within this report. This water use inventory describes the reported water usage quantities noted above and includes water usage quantities reported to the California State Water Control Board based on its current reporting requirements or reported directly to DWR to assist with this report. Existing domestic well information was obtained through document research conducted by DWR, generally using information provided previously by permitting agencies located in the four major counties situated within the basins; Placer, El Dorado, Nevada and Sierra Counties. While Alpine County occupies a very small part of the southern end of the Lake Tahoe Basin watershed, this alpine area is very remote and no diversions or water consuming developments have been identified or reported for this area. 2 This annual report also identifies new non-exempt groundwater wells that were constructed in the Truckee Basin during the year of record. These wells are typically permitted by the local permitting agencies within the applicable county and then reported to the State. During the 2016 calendar year, there were no such non-exempt wells reported to the state. Upon the implementation of TROA in late 2015, a water use inventory is now required to be prepared by California and Nevada for every calendar year and provided to the TROA Administrator by the end of the following third quarter (September 30). It was agreed by the TROA Administrator and the states of California and Nevada that calendar year 2016 would be the first year reported. It is anticipated that the accuracy and reliability of this annual inventory and the related water usage data related to California diversions, distribution sources and their respective annual uses will continue to evolve and be refined in subsequent years as additional information regarding existing inventories, their respective water use, metering and sewering methods, and reporting methods are improved. 3 This page intentionally left blank 4 Table of Contents Executive Summary ...................................................................................................................................... 1 Table of Contents .......................................................................................................................................... 5 Tables ............................................................................................................................................................ 5 Figures .......................................................................................................................................................... 5 Introduction ................................................................................................................................................... 7 Authority ....................................................................................................................................................... 9 Background ................................................................................................................................................. 11 Compliance with Public Law 101-618 and TROA ..................................................................................... 14 Water Use Inventory ................................................................................................................................... 14 Municipal and Industrial Use .............................................................................................................. 14 Private Domestic Wells ....................................................................................................................... 14 Water Purveyors