Inter-Departmental Correspondence

County Counsel



November 9, 2009


December 1, 2009


10 days notice per Government Code sections 65858 and 65090





Honorable Board of Supervisors


Lisa Grote, Director of Community Development

Dean Peterson, Director, San Mateo County Environmental Health

Michael P. Murphy, County Counsel


Adoption of Urgency Ordinance Amending, on an Interim Basis, Chapter 4.68 of the San Mateo County Ordinance Code to Prohibit the Issuance of Permits for the Construction of Water Wells in Certain Areas of the San Mateo County Midcoast



Adopt an urgency ordinance amending, on an interim basis, Chapter 4.68 of the San Mateo County Ordinance Code to prohibit the issuance of permits for the construction of water wells in certain areas of the San Mateo County Midcoast.



This Board determined to undertake a comprehensive study of hydrogeologic conditions in the Midcoast area of San Mateo County to assess whether a lack of service connections provided by appropriate water districts may affect the availability of sources of groundwater. As one component of this study, the County retained Kleinfelder Consultants to perform a San Mateo County Midcoast Groundwater Study, Phase II, and Kleinfelder has completed this study. The study identifies eight groundwater subbasins in the Midcoast (which are further divided into twenty-one subareas) and develops generalized water balance models for these subbasins/subareas, based on aquifer characteristics, average pumping rates, and rainfall amounts over a fifty year period.


Data in this study indicates that, given current usage rates, Midcoast aquifers that have groundwater surpluses in average rainfall years can have a deficit in dry years; that current pumping rates have lowered the water table in many aquifers to near sea level during dry years, posing the risk of saltwater intrusion; and that groundwater deficits may occur more frequently in the granitic aquifers underlying parts of the Midcoast than in other aquifers. The Kleinfelder report recommends that the County undertake further study and analysis to better define the hydrology of the Midcoast and a Phase III San Mateo County Midcoast Groundwater Study is currently underway. This Phase III Study is expected to recommend changes to the ways in which groundwater extractions are monitored, controlled, and distributed in order to ensure reliable and environmentally sustainable sources of water for existing and future Midcoast residents. Further, the various Midcoast groundwater studies will facilitate and serve as the basis for the development of a long-term Midcoast Groundwater Management Plan.



Upon review of the Kleinfelder report and based on other information available to the County, staff has identified certain subareas and subbasins, as identified in the Kleinfelder report, that may be particularly at risk for overutilization and resulting aquifer stress if groundwater extractions are increased. Specifically, the following subareas/subbasins have been identified: the Lower Moss Beach Subarea, the Dean Creek subarea, the Upper Moss Beach Subarea, the Lighthouse Subarea, the Portola Subarea, the Lower Montara Creek Subarea, and the Montara Terrace Subbasin.


In light of these risks, the threat to the public welfare would be alleviated by adoption of an interim ordinance restricting the issuance of water well permits in these subareas/subbasins pending completion of the Phase III Study, which will address the long term effects and viability of permitting further water wells in these areas.


This ordinance is being proposed as an urgency interim ordinance under the provisions of section 65858 of the California Government Code, which authorizes the County to adopt as an urgency measure an interim ordinance prohibiting uses that may be in conflict with a contemplated land use proposal that the County intends to study within a reasonable period of time. As discussed in the proposed findings and declarations included within the ordinance, there is a current and immediate threat to the public welfare that would result from the issuance of water well permits in the subareas/subbasins listed above. The ordinance, as presented, requires a four-fifths (4/5) vote and would be effective for forty-five days, after which may be readopted for a period of twenty-two and a half months (for a total of two years), while the County completes the Phase III groundwater study. The California Government Code requires ten days prior notice of this proposed action in a newspaper of general circulation, and such notice was given.


Adoption of these regulations is exempt from review under the California Environmental Quality Act under section 15061(b)(3) of Title 14 of the California Code of Regulations because there is no possibility that these regulations, which impose further restrictions on development, will have the potential to cause a significant effect on the environment.


This action contributes to the Shared Vision 2025 outcome of environmentally conscious community by ensuring proper management of groundwater resources for current and future County residents.



None anticipated.