Groundwater Condition

Transcription

1 Groundwater Condition REPORT SANTA CLARA COUNTY December 218 Groundwater Storage: Total storage at the end of 218 is predicted to fall within Stage 1 (Normal) of the District s Water Shortage Contingency Plan. Santa Clara Plain: o The November 218 managed recharge estimate is 4,7 acre-feet. The year-to-date managed recharge estimate is 73,4 acre-feet, or 145% of the five-year average. o The October 218 groundwater pumping estimate is 6,5 acre-feet. The year-to-date pumping estimate is 54,1 acre-feet, which is 79% of the five-year average. o The groundwater level in the Santa Clara Plain (San Jose) index well is about 9 foot lower than last November and 19 feet higher than the fiveyear average. Coyote Valley: o The November 218 managed recharge estimate is 9 acre-feet. The year-to-date managed recharge estimate is 9,8 acre-feet, or 118% of the five-year average. o The October 218 groundwater pumping estimate is 1, acre-feet. The year-to-date pumping estimate is 1,5 acre-feet, which is 19% of the five-year average. o The groundwater level in the Coyote Valley index well is about 6 feet lower than last November and 5 feet higher than the five-year average. Llagas Subbasin: o The November 218 managed recharge estimate is 1,2 acre-feet. The year-to-date managed recharge estimate is 16,8 acre-feet, or 96% of the five-year average. o The October 218 groundwater pumping estimate is 4,6 acre-feet. The year-to-date pumping estimate is 35,7 acre-feet, which is 96% of the five-year average. o The groundwater level in the Llagas Subbasin (San Martin) index well is about 26 feet lower than last November and 2 feet higher than the fiveyear average. Contact Us For questions, contact Bassam Kassab at (48)

2 December 218 Groundwater Condition Report Groundwater Recharge Compared to the November average of the last five years ( ), the estimated managed recharge for November 218 is lower for the Santa Clara Plain and Llagas Subbasin and higher for the Coyote Valley. Managed recharge is dependent on several factors, including water availability, regulatory requirements, and facility maintenance schedules. Figures 1, 2, and 3 compare monthly managed recharge in 218 to the fiveyear average. Figure 1 - Estimated Managed Recharge in the Santa Clara Plain 12, 1, Estimated Managed Recharge - Santa Clara Plain Acre-feet 8, 6, 4, 2, Average Figure 2 - Estimated Managed Recharge in the Coyote Valley 1,5 1,3 Estimated Managed Recharge - Coyote Valley Acre-feet 1, Average Figure 3 - Estimated Managed Recharge in the Llagas Subbasin 4, Estimated Managed Recharge - Llagas Subbasin Acre-feet 3, 2, 1, Average Page 2 of 1

3 December 218 Groundwater Condition Report Groundwater Pumping Estimated pumping for October 218 (the most recent month with pumping data available from retailers) is lower than the October average of the last five years ( ) for the Santa Clara Plain and higher for the Coyote Valley and Llagas Subbasin. Figures 4, 5, and 6 compare monthly estimated groundwater pumping through September 218 to the five-year average. Figure 4 Estimated Santa Clara Plain Pumping Acre feet 18, 16, 14, 12, 1, 8, 6, 4, 2, Estimated Groundwater Pumping - Santa Clara Plain Average Figure 5 Estimated Coyote Valley Pumping 2, Estimated Groundwater Pumping - Coyote Valley Acre-feet 1,5 1, Average Figure 6 Estimated Llagas Subbasin Pumping Acre-feet 8, 7, 6, 5, 4, 3, 2, 1, Estimated Groundwater Pumping - Llagas Subbasin Average Page 3 of 1

4 December 218 Groundwater Condition Report Groundwater Levels Groundwater levels at selected monitoring wells (Figure 7) are compared to the groundwater levels of November 1987 (a dry year), November 24 (a normal year), and the five-year average of November measurements for This information is presented in individual well groundwater hydrographs in Figures 8 through 18. November 218 groundwater levels were lower than October 218 levels in four index wells, higher in four wells, about the same in two wells, and one well lacks November 218 data. From November 217 to November 218, one index well showed a water level increase of 3 feet, eight wells showed water level decreases ranging from 3 to 26 feet, one well remained at the same level, and one well lacks November 218 data. The November 218 levels were higher than November 24 levels by 3 to 26 feet in six index wells, lower by 1 to 13 feet in two wells, remained the same in one well, one well lacks November 218 data, and one well lacks 24 data. November 218 levels were higher than the five-year average of November measurements in nine index wells by 2 to 25 feet, lower in one well by 3 feet, and one well lacks November 218 data. November 218 groundwater levels were higher than November 1987 levels in eight index wells, lower in two wells, and one well lacks November 218 data. Figure 7 - Location of Selected Monitoring Wells Page 4 of 1

5 December 218 Groundwater Condition Report Figure 8 - Milpitas Well Hydrograph Santa Clara Plain Well 6S1W24H15 (Milpitas) Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Dry Year 5 Year Average Depth to Water Between March 1998 and October 26, this well was observed to be flowing artesian. In October 26, the well was modified to allow measurement of artesian pressures. Therefore, a measured value for 24 is not available. Figure 9 Sunnyvale Well Hydrograph Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Santa Clara Plain Well 6S2W24C8 (Sunnyvale) Year Average 1987 Dry Year 24 Normal Year Depth to Water Page 5 of 1

6 December 218 Groundwater Condition Report Figure 1 - San Jose Well Hydrograph Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Santa Clara Plain Well 7S1W25L1 (San Jose) Dry Year 5 Year Average 24 Normal Year Depth to Water Figure 11 - Santa Clara Well Hydrograph Santa Clara Plain Well 7S1W2G24 (Santa Clara) Sep-213 Sep-214 Sep-215 Sep-216 Sep-217 Sep Dry Year 5 Year Average Depth to Water No static water level measurement is available for November 218. Page 6 of 1

7 December 218 Groundwater Condition Report Figure 12 - South Santa Clara Well Hydrograph Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Santa Clara Plain Well 7S1W8D3 (S. Santa Clara) Dry Year 5 Year Average 24 Normal Year Depth to Water Figure 13 - Campbell Well Hydrograph Santa Clara Plain Well 7S1W27P9 (Campbell) Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Dry Year (F1) 5 Year Average (F1) 24 Normal Year (F1) Depth to Water (7S1W34F1) Depth to Water The Campbell index well was replaced in August 215 with a nearby well with similar water level history. Comparisons with 1987, 24, and 5 year average are against the former index well (7S1W34F1) Page 7 of 1

8 December 218 Groundwater Condition Report Figure 14 - South San Jose Well Hydrograph Santa Clara Plain Well 8S2E18L1 (S. San Jose) Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Dry Year 5 Year Average 24 Normal Year Depth to Water Figure 15 - Coyote Valley Well Hydrograph Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Coyote Valley Well 9S2E2J2 (Coyote Valley) Dry Year 5 Year Average 24 Normal Year Depth to Water Page 8 of 1

9 December 218 Groundwater Condition Report Figure 16 - Morgan Hill Well Hydrograph Llagas Subbasin Well 9S3E22P5 (Morgan Hill) Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Dry Year 5 Year Average 24 Normal Year Depth to Water Figure 17 - San Martin Well Hydrograph Llagas Subbasin Well 1S3E13D3 (San Martin) Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Dry Year 5 Year Average 24 Normal Year Depth to Water No static water level measurement is available for September 218 since the well was pumping Page 9 of 1

10 December 218 Groundwater Condition Report Figure 18 - Gilroy Well Hydrograph Llagas Subbasin Well 11S4E1D4 (Gilroy) Nov-213 Nov-214 Nov-215 Nov-216 Nov-217 Nov Dry Year 5 Year Average 24 Normal Year Depth to Water Page 1 of 1