• Court Upholds City's Analysis of Groundwater Sufficiency
  • December 18, 2008
  • Law Firm: Bingham McCutchen LLP - Walnut Creek Office
  • For certain large projects, the Water Code requires water suppliers to prepare a “water supply assessment” to determine whether sufficient water supplies will exist for the project and other planned growth, over a 20-year horizon. The water supply assessment must be included in the EIR for the project, and its conclusion is subject to review by the lead agency upon project approval. In the first published decision to address the adequacy of a water supply assessment, the Court of Appeal upheld Rohnert Park’s assessment against claims that the analysis was inadequate because it used the wrong study area and failed to analyze future pumping throughout the relevant groundwater basin. O.W.L. Foundation v. City of Rohnert Park. (A114809, November 19, 2008)

    The Water Code requires a water supplier to prepare a water supply assessment that analyzes whether supplies are sufficient for certain large development projects. The assessment must describe whether the water agency’s projected water supplies available during normal, single dry, and multiple dry water years for a 20-year period will meet the projected water demand for the proposed project, along with the agency’s existing and planned future uses of water. If the water supply for the proposed project includes groundwater, the water supplier must analyze whether groundwater from the basin “will be sufficient to meet the projected demand associated with the project.”

    O.W.L. challenged a water supply assessment Rohnert Park prepared for six projects, the largest of which is a mixed-use specific plan. The trial court found the analysis faulty because it did not assess water demands and projected pumping by all groundwater users throughout the entire groundwater basin. It ruled that the Water Code required a “real analysis of the amount of water available,” which requires “a determination of the amount of water being used and expected to be used by everyone who uses the same water supply.”

    The court of appeal reversed. The court found that while the Water Code requires a determination of “sufficiency,” this requirement could not reasonably be interpreted to require preparation of a basin-wide study of current and future pumping. It observed that Water Code’s requirement for an estimate of the water supplier’s own past and projected pumping necessarily suggested the legislature did not intend to require information for all users in the groundwater basin. The court found it noteworthy that the legislature had originally considered and rejected language that would have required a water supply assessment to address the other groundwater users in the basin.

    The court also observed that, as a practical matter, requiring collection and analysis of basin-wide data would impose an enormous burden on water suppliers, particularly given the 90-day statutory deadline for completion of a water supply assessment. Because groundwater use is not regulated by the state, detailed information about pumping throughout many groundwater basins is not readily available. Further, given the massive size of some groundwater basins, the court found it unlikely the legislature had intended water agencies to analyze groundwater pumping throughout such huge basins merely to determine whether sufficient groundwater supplies exist for a single development project.

    The court pointed out that the infeasibility of a basin-wide analysis of groundwater uses within the local groundwater basin was clear from the record in the case. The Santa Rosa Valley Groundwater Basin is large and includes multiple jurisdictions. The court noted that it would require a “‘herculean effort” in the limited 90-day time frame for completion of an analysis of demand and supply in this basin:

    A water supply assessment is supposed to provide information about groundwater sufficiency for a specific, proposed development project. It is not a general planning document for the management of basin groundwater supplies. Other means exist to manage and regulate groundwater supplies, such as groundwater management plans, the adoption of groundwater ordinances, and groundwater adjudications by the courts. It is not appropriate to impose such a broad inquiry into basin-wide conditions upon water suppliers seeking to comply with section 10910(f)(5), the Water Code’s requirement for an assessment of groundwater sufficiency for a specific project. The intent of the statute is to ensure that local agencies take water supplies into account when considering new development, not to impose the burden of a basin-wide analysis of past and future groundwater conditions every time a new development project is proposed.

    O.W.L. also argued that the study area used in the City’s water supply assessment was defective because it was based on watershed boundaries. The court rejected this claim, finding that the city’s experts had chosen the study area based on prior hydrologic studies and independent analysis of subsurface geologic conditions and available groundwater data. The water supply assessment also contained a detailed discussion of the relationship between the watershed and the groundwater divide, and that analysis was supported by a prior hydrological study. Because the selection of the watershed as study area was based on an analysis of empirical data rather than an unsupported assumption, the court found it legally adequate.

    The court’s opinion provides valuable guidance on interpretation of the Water Code’s requirements for the preparation of water supply assessments. Of particular importance is the court’s recognition that water suppliers and their experts have substantial discretion to select methodology, and that reviewing courts will not second-guess the methodologies that are used as long as they are supported by rational analysis of the technical data.