Salt and Nutrient Management Plan Information

What is a Salt and Nutrient Management Plan (SNMP)?

The City of Poway distributes recycled water within the Poway Business Park. The Poway Groundwater Basin exists to the north of the Poway Business Park. The Poway Hydrologic Subarea spans both the Business Park and Ground Water Basin, providing a potential corridor for the applied recycled water to migrate between the business park and the groundwater. Recycled water is typically higher in salts and nutrients that have a potential to negatively impact water quality objectives and beneficial uses within groundwater basins.

The State Water Resources Control Board (SWRCB) adopted the Recycled Water Policy (Policy) in 2009 that requires Salt and Nutrient Management Plans (SNMP) be developed to manage salts, nutrients and other chemical compounds on a basin-wide basis. The Policy specifies that SNMPs are to be developed in a collaborative manner among water and wastewater agencies and other salt and nutrient stakeholders. The SNMPs are intended to help streamline the permitting of recycled water projects while ensuring compliance with water quality objectives and protection of beneficial uses.

How are Salt and Nutrient Management Plans Developed?

In an effort to help water agencies during the plan development process, the San Diego County Water Authority helped develop guidelines for agencies to follow when developing SNMPs. As part of the guidelines, groundwater basins were categorized based on size and complexity starting with Tier A groundwater basins being the largest and most complex, and Tier C being the smallest and simplest. The Poway Basin was originally categorized as a Tier B basin and later recategorized as a Tier C basin.

SNMPs are typically developed utilizing an engineering or environmental consultant specialized in groundwater management. Plans are primarily comprised of five main tasks:

• Initial basin characterization is done, with primary focuses on documenting the beneficial uses of the groundwater, identification of previous studies, identifying stakeholders, and collecting groundwater data.
• Sources of contaminants are identified and quantified by utilizing groundwater models.
• Gaps in information are identified and then additional data is collected.
• Management strategies are developed by the consultant in consultation with the City, which evaluates the best way to manage salts and nutrients that may be impacting the groundwater basin.
• Development of a monitoring program which will help to assess the effectiveness of the management strategies.

As part of the Salt and Nutrient Management Plan, the City is required to put together groundwater management strategies, taking into consideration the input from stakeholders (residents and business). Depending on the level of contamination that the City finds in the groundwater sampling program, management strategies could have a very little impact on residents and businesses or they could have long-range implications. For example, if it is found that the groundwater quality in the Poway basin is very poor because of fertilizer contamination, then the City may have to find ways to reduce the use of fertilizer in the groundwater basin.

Additionally, the plan development process takes into consideration the input from stakeholders that are interested in groundwater basin (well users, businesses, residents,, etc.).