MAGSA developing groundwater level metrics, sustainability criteria considered for individual wells

Setting metrics for groundwater level is underway in MAGSA. At the February 6th Board Meeting, technical consultant Lynn Groundwater, Provost & Pritchard, discussed MAGSA’s methodology for setting the criteria that indicates whether or not sustainable levels of groundwater are met. Known as sustainable management criteria, these levels are guided by historical groundwater level data. The Kings Subbasin coordinated effort has adopted MAGSA’s methodology, with a few variances such as time period of data used.

Sustainable Management Criteria are the SGMA metrics of success. The criteria will include numeric values for groundwater depth. These values will guide sustainability efforts. The first value is the measurable objective: the groundwater depth you must reach and maintain. The second value is the minimum threshold: the groundwater depth you cannot drop below. A range of flexible values, the operational flexibility, will also be determined. The operational flexibility takes into account historical declines and the potential for future drought occurrences. The intent of operational flexibility is to allow groundwater depths to drop for a time (e.g. during a drought) as long as recovery toward the measurable objective follows. 

Using data to determine historical rates of water level decline is important for setting reasonable sustainability objectives. Historical data helps set the objectives. Future data will inform Agency managers of progress occurring toward achievement of those objectives. MAGSA is using historical data beginning 1990-present from wells within its service area. Progress toward the sustainability objectives will be tracked using data collected from the monitoring network of spatially distributed wells.  Moving forward, MAGSA plans to collect groundwater level data from each well at least every March and October. Each well within the network will have its own minimum threshold and measurable objectives against which to measure new data.

Sustainability progress will follow a phased mitigation schedule, starting slowly at first with increased rate of progress over time. This allows time to begin developing management actions and building projects that may not yield the bulk of results until further down the GSP implementation road.  

As Groundwater Sustainability Plan (GSP) draft chapters take shape for internal review, technical consultants are actively seeking public input early on from stakeholders during Board meetings and via the Undesirable Results online survey. The input received prior to the official GSP 90-day public review period allows maximum stakeholder concerns and preferences to be considered and included in early GSP chapter drafts.