LAUREL MARCUS California Land Stewardship Institute OVERVIEW OF GROUNDWATER STUDIES IN THE RUSSIAN RIVER WATERSHED

Transcription

1 LAUREL MARCUS California Land Stewardship Institute OVERVIEW OF GROUNDWATER STUDIES IN THE RUSSIAN RIVER WATERSHED

2 - 60% OF LAND AREA } 20% OF LAND AREA } 20% OF LAND AREA GEOLOGY OF THE RUSSIAN RIVER WATERSHED

3 Diagram of pull apart basin formation along right-lateral slip faults The basins in the Russian River began developing about 4-5 million years ago. Boulders, gravel and sand/silt carried by landslides and debris flows from the mountains on both sides of the valleys created a series of alluvial layers filling each valley. The Russian River can redistribute this alluvium but is not the primary source

4 (Hopland) GROUNDWATER BASINS IN THE RUSSIAN RIVER WATERSHED

5 HYDROLOGIC CYCLE

6 REDWOOD, UKIAH, HOPLAND AND MCDOWELL VALLEYS Groundwater Basin Areal Extent Depth of Deposit Groundwater Well Production gallons per minute (gpm) Groundwater Storage Capacity Status of Ground water Level Redwood and Ukiah Valleys 59 sq. miles Alluvium ft.; Continental deposits 200 ft. Alluvium gpm Alluvium, terrace, river channel deposits, continental deposits: 324,000 ac-ft.; alluvium and terrace deposits only: ,000 ac-ft., river channel deposits only 35,000 ac-ft. Stable Hopland Valley 8.4 sq. miles Alluvium un- to semi confined - 50 ft.; Continental deposits ft. Alluvium 500 gpm; Continental deposits 1-50 gpm Alluvium 20,000 ac-ft. Stable McDowell Valley 2 sq. miles Alluvium 200 ft.; Continental deposits ft. Alluvium 500 gpm; Continental deposits 1-50 gpm Not available Stable From: California Department of Water Resources, California s Groundwater: North Coast Hydrologic Region Bulletin 118.

7 Franciscan Complex Franciscan Complex

8 Farrar, C.D Groundwater Resources in Mendocino County, California. U.S. Geological Survey. Water-Resources Investigations Report Cardwell, G. T., 1965, Geology and Groundwater in Russian River Valley Areas and in Round, Laytonville, and Little Lake Valleys, Sonoma and Mendocino Counties, California: U.S. Geological Survey, Water-Supply Paper 1548, scale 1:62,500.

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10 From Farrar 1986

11 From Ca. Dept of Water Resources

12 CA. Department of Water Resources Water Library Groundwater level data

13 Redwood Valley groundwater movement Ukiah Valley groundwater movement Lines show direction of groundwater movement from the mountains on both sides of the valley towards the river and from upstream to downstream. From Farrar 1986.

14 Conclusion from Farrar study None of the hydrographs (of well levels) show any prominent long-term declines. Analysis of the hydrographs indicates that the ground-water reservoir is recharged fully each year except when precipitation falls below about 60 percent of normal. After 2 years of drought, the reservoir can be fully recharged by 1 year of normal or above-normal precipitation. This report notes the need for more well data. Hopland groundwater movement From Farrar 1986.

15 Connection to Salmonids: Flow in tributaries in Ukiah Valley varies with stage of Russian River

16 RIVER CHANNEL AND GROUNDWATER BASIN PRIOR TO RIVER CHANNEL ENTRENCHMENT MOUNTAINS River channel MOUNTAINS Groundwater basin in alluvial valley of Russian River RIVER CHANNEL AND GROUNDWATER BASIN AFTER RIVER CHANNEL ENTRENCHMENT SUMMER TIME GROUNDWATER LEVEL IS LOWER

17 Drop in ground water levels along creek coincides with the drop in flow levels in the main river channel. Drop is greatest in the well located closest to the Russian River indicating that the river s water surface elevation is controlling the groundwater level of the tributaries. Flow in both Morrison and Parsons Creeks went subterranean as soon as the water level in the mainstem river dropped. No juvenile steelhead could have migrated out of these creeks which have year round flow in their canyons. From Jackson and Marcus 2004

18 MOUNTAINS HIGH RIVER FLOW MOUNTAINS ALLUVIAL BASIN WITH GROUNDWATER ENTRENCHED RIVER CHANNEL DURING AND AFTER RAINSTORM- CREEK EXITING MOUNTAINS AND CROSSING ALLUVIAL BASIN MORRISON CREEK AT HIGH FLOW IN FEBRUARY 2009.

19 MOUNTAINS LOW RIVER FLOW MOUNTAINS Steep slope = rapid percolation ENTRENCHED RIVER CHANNEL ALLUVIAL BASIN WITH GROUNDWATER DURING AND AFTER RAINSTORM- CREEK EXITING MOUNTAINS AND CROSSING ALLUVIAL BASIN When stage of river is dropped water in tributary creek goes subterranean stranding any fish in the creek

20 ALEXANDER VALLEY Groundwater Basin Alexander Valley - Cloverdale sub-basin Alexander Valley - Alexander Valley subbasin Areal Extent 10 sq. miles 37 sq. miles Depth of Deposit Groundwater Well Production gallons per minute (gpm) Groundwater Storage Capacity Status of Ground water Level Alluvium ft. Alluvium gpm 55-71,000 ac-ft. Stable ft gpm 762,000 ac-ft. Stable From: California Department of Water Resources, California s Groundwater: North Coast Hydrologic Region Bulletin 118.

21 From: Metzger, L. E., C. D. Farrar, K.M. Koczot, and E. G. Reichard Geohydrology and Water Chemistry of the Alexander Valley, Sonoma County, California. U.S. Department of the Interior, U.S. Geological Survey.

22 Cross section A through the Cloverdale basin. From Metzger Cross section A depicts a section of the Cloverdale basin. A series of monitoring wells are also shown. The drilling logs for these wells were used to determine subsurface geology. In the Cloverdale basin recent alluvium (Qal) fills the groundwater basin atop a thick layer of Franciscan Complex (TKJF). In general Franciscan Complex is non-water bearing except where fractures occur.

23 Cross section B near Geyserville in the Alexander Valley basin. From Metzger Cross section B-B is located across the valley just north of Geyserville. It shows recent alluvium filling the Alexander Valley groundwater basin atop Franciscan Complex. The depth of alluvium is much greater than the Cloverdale basin.

24 Cross section C near Jimtown in the Alexander Valley basin. From Metzger Cross section C-C lies across the valley just to the north of Jimtown. It depicts more complex subsurface geology with wells accessing water in the relatively shallow recent alluvium and the thicker deposit of Glen Ellen Formation. Sonoma Volcanics and Franciscan Complex also occur in the cross section.

25 From: Ca. Dept of Water Resources

26 Groundwater levels 1980 Groundwater levels 2002 From Metzger 2006

27 Metzger et al (2006) completed a detailed review of nine well records in Alexander Valley and identified a slight decline in groundwater levels termed a small imbalance between groundwater use and recharge. This decline primarily occurred in wells between Geyserville and Jimtown. This report notes the small number of well records used and the need for more well data.

28 SANTA ROSA PLAIN Groundwater Basin Santa Rosa Valley - Healdsburg sub-basin Santa Rosa Valley - Santa Rosa subbasin Areal Extent 245 sq. miles 125 sq. miles Depth of Deposit Alluvium ft.; Wilson Grove Formation ft. Alluvium ft.; Wilson Grove Formation ft; Glen Ellen Formation ft. Groundwater Well Production gallons per minute (gpm) Alluvium gpm; Terrace deposits gpm; Glen Ellen Formation gpm Alluvium gpm; Wilson Grove Formation gpm; Glen Ellen Formation 10 gpm Groundwater Storage Capacity Status of Ground water Level 489,000 ac-ft. Stable 4,313,000 ac-ft. Stable From: California Department of Water Resources, California s Groundwater: North Coast Hydrologic Region Bulletin 118.

29 From: Nishikawa, Tracy ed Hydrologic and Geochemical Characterization of the Santa Rosa Plain Watershed, Sonoma County, CA. U.S. Geological Survey Scientific Investigations Report

30 From Nishikawa 2013

31 From Nishikawa 2013

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33 From Nishikawa 2013

34 From Nishikawa 2013

35 From Nishikawa 2013

36 From Nishikawa

37 From Nishikawa

38 Summary from USGS report Nishikawa 2013 : Hydrogeology Groundwater is contained in the pore spaces of the Quaternary alluvial materials and Tertiary sedimentary rocks, including the Glen Ellen Formation, the Wilson Grove Formation, the Petaluma Formation, and Sonoma Volcanics. The source of natural recharge is precipitation falling on the Santa Rosa Plain and on the surrounding mountains. There is limited hydraulic communication between shallow and deeper aquifer systems There is limited groundwater underflow across the Rodgers Creek fault zone from the uplands to the Santa Rosa Plain. The Sebastopol fault could be a partial barrier to groundwater flow.

39 Water Use Reported public-supply pumpage averaged 6,800 acre-feet per year and makes up 18% of total groundwater use Estimated agricultural pumpage averaged 12,500 acre-feet per year and makes up 32% of total groundwater use Estimated domestic (rural residential) pumpage averaged 19,300 acre-feet per year and makes up 50% of total groundwater use Total evapotranspiration from the soil, unsaturated, and saturated zones estimated by a preliminary watershed model was about 265,700 acre-feet per year.

40 From Sonoma County Water Agency 2014

41 Groundwater movement The 1951 (predevelopment) water-level contour map shows that groundwater flowed from the Mayacmas and Sonoma Mountains westward toward the Laguna de Santa Rosa and eastward from the highlands toward the Laguna de Santa Rosa. The groundwater-level contour map also shows that groundwater moved toward, and discharged into, the stream channels, thereby, likely sustaining baseflow. Groundwater levels In the Windsor Basin storage unit, water levels were fairly steady with some seasonal variability, and some hydrographs showed the effects of the and droughts. In the Cotati Basin storage unit, water levels from wells in the area near Rohnert Park recovered to 1974 conditions by 2007 as a result of a large reduction in municipal pumping that began in From 1975 to 2010 annual loss has been around 3,300 acre feet per year primarily in deeper >200 ft wells. This represents 4% of the average total amount of groundwater flowing into the basin. However, because it is cumulative, the relatively small annual loss can lead to declines in groundwater levels and reduced water flows in creeks and streams.

42 Data Gaps Lack of depth-dependent water-level and water-quality data make it difficult to calibrate a groundwater-flow model by aquifer or layer. Additional water-quality data are needed to help explain variability in observed water-quality data in the Cotati Basin storage unit. Better estimates, or direct measurements, of agricultural and domestic pumpage are required to improve calibration of a numerical groundwater and surface-water flow model. The locations of these wells are often unknown or unreported; therefore, the locations of these wells should be determined.

43 Upper Mark West Creek Watershed From CEMAR 2015 CEMAR in conjunction with NOAA Fisheries evaluated a number of features of one area in Upper Mark West Creek located upstream of the confluence of Mark West and Humbug Creeks. Local residents had expressed concerns that these creeks were drying up when previously they had not and that upstream agricultural development and wineries were largely the cause. This 14 sq. mile section of the watershed receives an average of 46.3 inches of rainfall annually.

44 From CEMAR 2015 This study determined 158 acres of vineyard are located in this subset of the Upper Mark West Creek watershed. The study assumes a vineyard irrigation water demand of 0.3 ac-ft/acre/year for a total of 48 ac-ft. or 27% of the total It was determined there was a total of 222 houses with a footprint of 2.94 acres. Rural residential use of 245 gallons/day/household for the dry season totals 126 ac-ft/dry season or 72% of the total Winery water use was estimated at 1.83 ac-ft/year or 1% of the total The total water demand of ac-ft/year

45 From CEMAR 2015 The hydrographs from 3 stations in Mark West Creek do not show sudden large changes as direct diversions from the creek would cause. However for the relatively short period of record ( ) examined in this study low flow conditions dominated each summer season. The study hypothesizes that the use of wells by most homeowners and growers is responsible for the low flow conditions.

46 From CEMAR 2015 These 52 residential wells produce relatively low volumes of water. The proximity of several wells near the stream in the ash-flow tuff and sand/gravel geological formations which have a high potential stream flow depletion factor suggests that wells operating in this region could individually or cumulatively have adverse effects on stream flow in Mark West Creek during the dry season.

47 From CEMAR 2015 Groundwater seeping into Mark West Creek provides the primary source of water to Coho salmon and steelhead trout summer rearing habitat. Sonoma Volcanic rocks are the primary source of this groundwater. This geologic formation is also the primary source of water for rural residences.

48 This study reviewed the initial depth to water in the drilling logs for 35 wells built between the 1970's and Clusters of wells near houses were reviewed but only a weak trend of lower water level was found. The study also discussed the effects of a vineyard well in Franciscan Complex on a ridge top above the North Fork of Mark West Creek. The well produces 10 gpm and is likely accessing water in a fracture in the rock. The well would only reduce seepage into the creek from one fracture. Calculating in the vineyard water demand the well removed.016 cfs during the June to September irrigation period. This amount is not enough to dewater the North Fork Mark West Creek. The study suggests that the drought and a large deposit of gravel upstream of an undersized culvert at St. Helena Road are the primary causes of the dewatering of this creek. From CEMAR 2015

49 CEMAR evaluated rainfall, runoff and water demand as part of the Goldridge RCD (2013) plan for Green Valley Creek. The model estimated that 52% of rainfall becomes evapotranspiration, 41% becomes runoff and 7% recharges groundwater. Water demand was estimated as 0.67 acre feet per acre per year for vineyard irrigation for a total of 411 acre feet per year, and acre feet per rural residential building for a total of 405 acre feet per year.

50 Summary Groundwater in the Russian River is complex due to the highly variable geology There is a slight imbalance between extraction of water and recharge in two basins in Sonoma County There is no documented imbalance in the Redwood-Ukiah-Hopland valley basin There is inadequate data on groundwater levels and groundwater pumping in all the basins Groundwater is the primary source of water for summer rearing of salmonids Water use figures for vineyard irrigation in groundwater studies vary considerably: 0.25 ac-ft/acre/year in Dry Creek Valley, 0.6 ac-ft/acre/year in all valley floor areas, 0.67 ac-ft/acre/year in the Sebastopol area, 0.3 ac-ft/acre/year in Upper Mark West Creek, 0.79 ac-ft/acre/year for Ukiah Valley, 0.58 ac-ft/acre/year for Sonoma County. There needs to be clarification of these figures based on water use reporting from growers.