4 *Contours generalized for estimating average watershed precipitation; adopted from larger map by Geomatrix, 1999.

Transcription

1 Selected USGS Stream Gaging Stations San Lorenzo River watershed A. Pescadero Ck B. San Lorenzo R. Waterman Switch C. Boulder Ck D. Zayante Ck E. Bean Ck F. San Vicente Ck G. San Lorenzo R. at Big Trees A SLVWD diversion watershed 4 Isohyetal (in/yr)* Precipitation station used in mapping. Selected precip. stations: 1. Lockheed 2. SLVWD Office 3. Ben Lomond 4 4. Santa Cruz B 1 C 2Boulder Creek Ben Lomond Quail 3 Hollow D Olympia E F Felton Scotts Valley Pasatiempo G Pa cif i co ce an 4 *Contours generalized for estimating average watershed precipitation; adopted from larger map by Geomatrix, Santa Cruz 2 miles SLVWD Water Supply Master Plan Figure 3-1. Isohyetal Map of San Lorenzo Valley

2 Tropical moisture entrained in jet stream. a. Cold Cyclonic Storm b. Warm Advective Storm Figure 3-2 Satellite Images of Typical Pacific Storms Imagery source: SLVWD Water Supply Master Plan

3 Santa Clara Valley Figure 3-3 Radar Image Showing Influence of Ben Lomond Mountain on Rainfall Distributon Southwest Average Annual Precipitation (in/yr) Northeast <3" " 6+" " <4" +" 3" 2" 1" Coast Davenport Santa Cruz Bonny Doon Ben Lomond Mtn. SLVWD Watersheds San Lorenzo River San Lorenzo Valley Scotts Boulder Ck Valley Ben Lomond Felton Summit Castle Rock Mt. Bielawski Santa Cruz Mountains Santa Clara Valley Los Gatos San Jose South San Francisco Bay Figure 3-4 Schematic Coast-to-South Bay Profile Illustrating Orographic Influence on Rainfall Distribution (adopted from Geomatrix, 1999; see Fig. 3-3 for approximate line of profile) ppt-xsec4.xls Fig 6/7/27 4:18 AM

4 2% Percent of Average Annual Rainfall 2% 1% 1% Ben Lomond 4, WY's Santa Cruz, WY's Lockheed, WY's % % Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep a. Comparison of Three Rainfall Stations 2% Percent of Average Annual Rainfall and Streamflow 2% 1% 1% % Average of 3 Rainfall Stations (Table 3-4) Average of 6 Gaged Streams (Table 3-9) % Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep b. Rainfall versus Streamflow Figure 3- Monthly Average Rainfall and Streamflow, Selected Stations Ppt-SC-LH4.xls Fig-MthAvg 6/7/27 4: AM

5 1% 1 9% 8% Percent of Time Rainfall is Less Than 7% 6% % 4% 3% 2% Cumulative Rainfall (inches) 1 1 Max. Rainfall* (inches) Date(s) 1-day 11. 1/4/82 2-day /4-/82 3-day /3-/82 7-day 2.4 2/12-18/86 14-day /18-31/ 21-day /3-2/19/86 3-day /26-2/24/98 *Based on daily readings.1 1-DAY 2-DAY 3-DAY 7-DAY 14-DAY 21-DAY 3-DAY.1 % 1% 2% 3% 4% % 6% 7% 8% Source: Percent of Time Rainfall is Greater Than Figure 3-6 Frequency of Cumulative Daily to Monthly Rainfall at Ben Lomond, BL4-Daily-Hist2.xls Fig 6/7/27 4:19 AM

6 Annual Rainfall (% f avg) 2% 1% 1% % Santa Cruz % Water Years Annual Rainfall (% f avg) 2% 1% 1% % Lockheed Facility % Water Years Years with 7% average rainfall Years with 76-9% average rainfall Apparent Santa Cruz upward trend partially explained by likely change(s) in station location pre-19, as indicated by double mass curve analysis (Geomatrix, 1999). Since 19, Santa Cruz upward trend continues while Lockheed trend becomes flat. Significance of Ben Lomond upward trend uncertain due to short record length. Source: see Tables 3-1 through 3-4. Ben Lomond 4 Annual Rainfall (% f avg) 2% 1% 1% % Figure 3-7 Water-Year Rainfall at Santa Cruz, Lockheed, and Ben Lomond Staions % Water Years Ppt-SC-LH6.xls Fig-WYs /18/29 6:16 AM

7 22% 2% Santa Cruz Lockheed Ben Lomond 4 Moving-Average Rainfall (percent of average) 17% 1% 12% 1% 7% Maximum for Period Minimum for Period % 2% Length of Moving Average Period (yrs) Moving-Average Minimums* Moving-Average Maximums* Yrs Santa Cruz Lockheed Santa Cruz Lockheed 1 3% % % % % % % % % % % % *Color-coded by common overlapping periods. 4 66% % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % % Figure 3-8 Minimum and Maximum Moving- Average Rainfall Ppt-SC-LH4.xls FigMvAvg 6/7/27 4:1 AM

8 2% 1% Cumulative Departure from Average (% of average) % -1% -2% -3% -4% -% Pre-189 Drought Drought Drought Drought -6% Lockheed (entire record) Santa Cruz (since 1889) Santa Cruz (entire record) Drought = downward segments Average period = flat segments Wet period = upward segments -7% Water Years Figure 3-9 Water-Year Rainfall Cumulative Departure from Average Ppt-SC-LH6.xls FigCumDepAvg /18/29 6:17 AM

9 8 3 8 Source: Reference Evapotranspiration (ETo, inches) Monthly CIMIS Reference Evapotranspiration for Santa Cruz County Zones Zone 1 -- Coastal Fog Belt Zone 2 --Coastal Mixed Fog Zone 3 -- Coastal Valleys Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 3-1 CIMIS Reference Evapotranspiration for Central Coast Region CIMIS Map2.xls CentralCoast 6/7/27 4:2 AM

10 Palo Alto a 6b Pilarcitos Ck at Half Moon Bay Purisima Ck near Half Moon Bay San Gregorio Ck at San Gregorio Pescadero Ck near Pescadero Butano Ck near Pescadero Scott Ck above Little Ck Scott Ck near Davenport San Vicente Ck near Davenport Laguna Ck near Davenport Majors Ck near Santa Cruz San Lorenzo R at Waterman Switch Boulder Ck at Boulder Creek Bear Ck at Boulder Creek Newell Ck at Ben Lomond Zayante Ck at Zayante Bean Ck near Scotts Valley San Lorenzo River at Big Trees 17 Carbonera Ck at Scotts Valley 18 Branciforte Ck at Santa Cruz 19 West Br. Soquel Ck near Soquel 2 Soquel Ck near Soquel 21 Soquel Ck at Soquel 22 Aptos Ck near Aptos 23 Aptos Ck at Aptos 24 Corralitos Ck near Corralitos 2 Corralitos Ck at Freedom 26 San Francisquito Ck at Stanford University 27 Saratoga Ck at Saratoga 28 Los Gatos Ck at Los Gatos 29 Guadalupe Ck at Guadalupe 3 Uvas Ck above Uvas Res near Morgan Hill 31 Bodfish Ck near Gilroy 32 Pescadero Ck near Chittenden (See Table 3-8 for summary of gaged records) Los Gatos n ea Oc ic cif Pa Morgan Hill SLVWD Diversions Davenport Figure 3-11 USGS Gaged Watersheds in the Santa Cruz Mountains Region (adopted from Geomatrix, 1999) Santa Cruz

11 3 Ben Lomond Mtn Adjusted to average (Table 3-8) 2 SLVWD diversion watershed estimate* Soil-Water Budget Estimates (Table 3-6) Quail Hollow Zaynte Soils Laguna Watershed Average Unit Streamflow (in/yr) Bodfish Pescadero San Gregorio San Francisquito Santa Cruz Pilarcitos Carbonera Ben Lomond Scott above Little Bean Uvas SLRBT WB SoquelMajors Scott Soquel at Sq Los Gatos Saratoga Branciforte Bear Zayante Butano Corralitos at Cor Newell Soquel SLR at Waterman Switch Apots near Aptos near Sq Guadalupe Pescadero Purisima Aptos at Aptos Corralitos at Fdm San Vicente Boulder *Adopted from Geomatrix, See Figure 3-11 for map of gaged watersheds. Watershed Average Rainfall (in/yr) Figure 3-12 Correlation Between Estimated Mean Annual Rainfall and Unit Streamflow for USGS Gaged Streams in the Santa Cruz Mountains Region ppt-q-4.xls Fig 6/7/27 4:12 AM

12 Annual Streamflow (% f avg) 3% 2% 2% 1% 1% % San Lorenzo River at Big Trees* % Water Years *Adjusted (Table 3-9) 4% Pescadero Creek 3% Annual Streamflow (% f avg) 3% 2% 2% 1% 1% % % Years with % average streamflow Years with -9% average streamflow Water Years Figure 3-13 Water-Year Streamflow of San Lorenzo River and Pescadero Creek Source: see Table 3-1. Sec3 USGS-Gaged-Records2.xls Fig-WY /18/29 6:34 AM

13 4 Pescadero Creek near Pescadero Boulder Creek at Boulder Creek 1 1 Mean Daily Streamflow (cfs) San Lorenzo River at Waterman Switch Zayante Creek at Zayante 1 1 San Lorenzo River at Big Trees 1 Oct-74 Oct-7 Oct-76 Oct-77 Oct-78 Oct-79 Oct-8 Oct-81 Oct-82 Oct-83 Oct-84 Oct-8 Oct-86 Oct-87 1 Oct-88 Oct-89 Oct-9 Oct-91 Oct-92 Oct-93 Bean Creek near Scotts Valley Oct-94 Plots show and droughts. Note effect of October 1989 Loma Prieta earthquake. 1 Source: Figure 3-14 Mean Daily Streamflow, Selected Streams, WY's Oct-88 Oct-89 Oct-9 Oct-91 Oct-92 Oct-93 Oct-94 Drought-HGs.xls Sheet1 6/7/27 4:23 AM

14 3% San Lorenzo River flow* vs Ben Lomond rainfall (WY's ; dated) '83 2% San Lorenzo River flow* vs Lockheed rainfall (WY's ) Boulder Creek flow vs Ben Lomond rainfall (WY's ) '82 Water-Year Streamflow (% of average) 2% 1% 1% San Lorenzo River vs Lockheed wet- & dryperiod averages (WY's ) Gaged watershed averages (as % of average for all watersheds; Table 3-8, Fig. 3-12) Soil-water budget estimates (as % of average for all cases; Table 3-6) '84 '4 '7 '99 '3 '97 '74 '8 '96 ' '93 '9 '86 '78 ' '6 '98 % '76 '77 '81 '87 '9 '91'94 '88 '89 '1 '79 '92 '8 '2 % 2% % 7% 1% 12% 1% 17% 2% Water-Year Rainfall (% of average) *At Big Trees gage; approx. adjustment for major diversions. See Tables 3-8 & -1 for sources. Figure 3-1 Correlation Between Annual Rainfall and Unit Streamflow Selected Periods of Gaged Record USGS-Gaged-Records2.xls Fig-WY-Ppt-Q 6/7/27 4:16 AM

15 Pescadero Creek, WY's San Vicente Creek, WY's Mean Daily Flow (cfs) Stormflow Baseflow Mean Daily Flow (cfs) Stormflow Baseflow 2 1-Oct 1-Nov 1-Dec 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 3 1-Oct 1-Nov 1-Dec 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 8 2 San Lorenzo River at Waterman Switch, WY's Boulder Creek, WY's Mean Daily Flow (cfs) Stormflow Baseflow Mean Daily Flow (cfs) Stormflow Baseflow 1-Oct 1-Nov 1-Dec 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 4 1-Oct 1-Nov 1-Dec 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep Zayante Creek, WY's Bean Creek, WY's Mean Daily Flow (cfs) Stormflow Baseflow Mean Daily Flow (cfs) Stormflow Baseflow Mean Daily Flow (cfs) 1-Oct 1-Nov 1-Dec 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep San Lorenzo River at Big Trees, WY's Stormflow Baseflow 1-Oct 1-Nov 1-Dec 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep Watershed Drainage Rainfall Area Unit Streamflow* Total * Baseflow Storm Runoff (% of Stream (mi 2 ) (in/yr) Total) (in/yr) Pescadero Ck % San Vicente Ck % SLR at Waterman Switch % Boulder Ck % Zayante Ck % Bean Ck % SLR at Big Trees % *Normalized to ; thus, values of total streamflow differ slightly from Table 3-8. ET Hydrographs are of average mean daily flow for indicated periods of record. Source: Figure 3-16 Estimated Avearge Stormflow-Baseflow Hydrograph Separation, Selected Gaged Streams Qb-summary2.xls Sheet1 6/7/27 4:24 AM

16 7 Annual Average Temperature (of) Santa Cruz y = -.168x y =.369x y =.97x Annual Average Temperature (of) Ben Lomond 4 y =.17x y =.71x y = -.33x y =.8x Annual Average Temperature (of) San Gregorio 2SE y =.7x y =.14x Annual Average Temperature (of) 7 7 y = -.112x Los Gatos 6 y =.126x y =.366x Source: Figure 3-17 Annual Mean Temperature, Selected Stations, Temp-SC.xls Sheet7 6/7/27 4:2 AM

17 From: CDWR, July 26.. Santa Cruz Lockheed y =.1x +.27 y =.13x Coefficient of Variability Source: see Table Water Years Figure 3-18 Coefficient of Variation for Moving 1-Year Periods of Annual Precipitaion, Study Area and Statewide, 188's to Present Ppt-SC-LH4.xls Fig-CoefVar 6/7/27 4:4 AM