The ground beneath our feet is not uniform; in fact it consists of many different sediment layers that can vary in consistency from fine particles (clay) to coarser sands and gravels. Generally, coarser materials like sands and gravels allow water to move through them more freely. Geologic layers consisting of these coarser materials are called aquifers. It is important to note that an aquifer is not usually a cavern under the ground that is filled with water, rather it is geologic formation in which the spaces between the granular particles are filled with water.
The shapes of the aquifers in our county have been subjected to slow deformation over very long periods of time (millions of years). Although the sediments in our aquifers were originally laid down horizontally, over geologic time they were bent upwards and downwards. So, the same aquifer that is several hundred feet deep at one location in the county can be exposed at the ground surface at another location. This is the case in Santa Cruz County where the geologic formations that serve as deep aquifers in the Pajaro Basin are exposed at the ground surface in the mid-county area of Aptos.
The Sustainable Groundwater Management Act (SGMA) in Santa Cruz County
Santa Cruz County has three basins that will be regulated under SGMA:
The Santa Margarita Basin forms a roughly triangular area between Felton, Ben Lomond, and Scotts Valley. This Basin provides drinking water for the Scotts Valley and San Lorenzo Valley Water Districts, over a dozen small water systems, and around 1100 parcels served by private wells. Additionally, the groundwater table influences the surface water in the San Lorenzo River, a primary drinking water source for the city of Santa Cruz and a home to endangered species.
The Mid-County Groundwater Basin encompasses the area East of the Santa Margarita basin and includes Live Oak, Soquel, Aptos, and Capitola. It provides water to the Soquel Creek and Central Water districts, the City of Santa Cruz, over 20 small water systems, over 1900 parcels served by private wells. It also provides habitat for endangered species and water for agriculture. This basin is in critical overdraft.
The Pajaro Basin is to the East of Mid-County ending on the South side of the Pajaro River in Monterey County. The basin provides water to the City of Watsonville, numerous private parcels, the thriving agricultural industry, and endangered species. This basin is in critical overdraft.