Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Groundwater topic
No spam. Unsubscribe anytime.
GSI contour report shows suspected nitrate hotspots; GM warns data are limited
Summary
A contour report from consultant GSI indicates areas at or above the nitrate MCL in parts of the district, but the general manager emphasized the contours are speculative without full flow/well data and urged additional testing.
The district shared new contour mapping by consultant GSI that identifies potential nitrate concentrations at or above the federal maximum contaminant level (MCL) of 10 mg/L in parts of the service area. General Manager (S3) stressed that the contours are an educated best guess because the district lacks full groundwater flow data and monitoring from wells north of the district.
"The dotted line to your point is where they try and draw...we think the boundary looks like this," General Manager (S3) said while explaining the map, adding that contour lines indicate areas where monitoring well readings hit or exceed an MCL of 10. He said further sampling and flow testing are needed to determine how much nitrates are coming from inside versus north of the district.
Directors asked staff to qualify map legends and label dotted lines as speculative to avoid misleading the public. Board members acknowledged the contours are useful as a preliminary tool but emphasized the need for empirical flow data to confirm sources and exact boundaries.
