Title
Consider receiving the 2019 Historical Seawater Intrusion Maps
Report
RECOMMENDATION:
It is recommended that the Monterey County Water Resources Agency Board of Directors:
Receive the 2019 Historical Seawater Intrusion Maps
SUMMARY/DISCUSSION:
Each summer, Agency staff samples approximately 120 agricultural, urban purveyor, and small diameter monitoring groundwater wells in the coastal area of the northern Salinas Valley. Water quality samples are collected from the agricultural and urban wells twice, once in June and again in August. The Agency’s network of small diameter monitoring wells is sampled once in September.
Samples are analyzed by the County’s Consolidated Chemistry Lab (ELAP # 1395). The data are then evaluated with several geochemical tools and contours are developed using an ArcMap interpolation tool and supporting data from several other Agency Programs. The new polygons are then added to the Historical SWI maps.
In 2019 the 500 mg/L or greater chloride areas show a small amount of advancement along the southern most lobe in the Pressure 180-Foot aquifer.
Within the Pressure 400-Foot aquifer the 500 mg/L or greater chloride areas also advanced a small amount in the southern most lobe. Additionally, and most alarmingly two of the “islands” in front of the main contours continued to expand.
OTHER AGENCY INVOLVEMENT:
None
FINANCING:
There is no financial impact for receiving these reports. The activities associated with completing these maps are funded through Funds 111 and 116 and included in each year’s budget.
Prepared by: Howard Franklin, Senior Hydrologist, (831) 755-4860
Tamara Voss, Associate Hydrologist, (831) 755-4860
Nicole Koerth, Water Resources Technician, (831) 755-4860
Mitch Krieger, Water Resources Technician, (831) 755-4860
Approved by: Brent Buche, General Manager, (831) 755-4860