Martis Valley Groundwater Management Plan - Placer County Water ...

Section 2
Physical Setting
The MVGB is located in the transition zone between the Sierra Nevada and the Basin and Range
Geomorphic Provinces, east of the Sierra Nevada crest and part of the larger Tahoe-Truckee River Basin
of California and Nevada. Martis Valley is the principal topographic feature within the MVGB. The
surrounding landscape is mountainous, underlain by volcanic and, to some extent, granitic bedrock, with
apparent faulting and some portions that have been glaciated. A significant portion of the land within the
MVGB boundary is privately owned with some areas managed as forest, open space and/or for
recreation by special districts or agencies, including the U.S. Forest Service. This section of the GMP
characterizes the physical setting of the MVGB, including: topography, climate, surface water hydrology,
geology, hydrogeology, and water use.
2.1 Topography
The MVGB encompasses roughly 57 square miles, and lies within the Middle Truckee River Watershed.
Elevations of the valley floor range from 5,700 to 5,900 feet above mean sea level (msl). The valley is
accented by hills rising above the valley floor and mountains to the south and east of the valley. High
points within or immediately adjacent to the MVGB include Bald Mountain at an elevation of 6,760 feet
and Alder Hill at 6,733 feet, located on the western margin of the MVGB, and Lookout Mountain at
8,104 feet and Mt. Pluto at 8,617 feet, located on its the southern fringe. Martis Peak, further to the
east, is at 8,742 feet. Figure 2-1 illustrates the MVGB location and topography.
2.2 Climate
The Tahoe-Truckee region experiences warm and dry summers, and cold, wet and snowy winters.
Elevation and rain shadow play major roles in the spatial distribution of temperature and precipitation.
Precipitation is highest at upper elevations in the western portion of the basin, toward the Sierra Crest,
and decreases with elevation in the eastern portion of the basin (Figure 2-2). Mean annual precipitation
(as snow water equivalent) ranges from approximately 30 inches below 6,500 feet to over 45 inches
above 6,500 feet. Precipitation falls mostly as snow between October and April, though runoff and
streamflow also responds to periodic mid-winter rain-on-snow events. Annual peak streamflow typically
occurs during spring snowmelt in May or June. A small proportion of the total annual precipitation falls
during brief thunderstorms in the summer months. Average monthly precipitation is shown in Figure 2-3,
as recorded at the United States Forest Service (USFS) Truckee Ranger Station, near the center of the
watershed (California Data Exchange Center Station TKE). Average temperatures range from daily lows
of 15ºF in December and January to daily highs of 82ºF in July, as recorded at SNOTEL Station
Truckee #2.
DRAFT for review purposes only. Use of contents on this sheet is subject to the limitations specified at the end of this document.
P:\40000\140691 - PCWA Martis Valley GWP\GMP\Report\3rd Draft\Martis Valley GMP Draft 01-09-13.docx
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