Title
Consider receiving Draft 2020 Historical Seawater Intrusion Maps.
Report
RECOMMENDATION:
It is recommended that the Basin Management Advisory Committee:
Receive the Draft 2020 Historical Seawater Intrusion Maps.
SUMMARY/DISCUSSION:
2020 Seawater Intrusion (SWI) Maps
ach 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 are 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 2020 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 northern most lobe, near Castroville. Additionally, two of the “islands” in front of the main contours, the middle one and the large southern one joined. This occurred in the area of Nashua and Cooper Roads.
OTHER AGENCY INVOLVEMENT:
None
FINANCING:
There is no financial impact in receiving this report.
Prepared by: Howard Franklin, Senior Hydrologist, (831) 755-4860
Tamara Voss, Associate Hydrologist, (831) 755-4860
Nicole Koerth, Hydrologist, (831) 755-4860
April Woods, Water Resources Technician, (831) 755-4860