Why Upgrade The Causeway


The purpose of the project is to develop and implement a nutrient management plan that does the following:

  1. Identifies alternatives that meet the impending regulatory requirements of the Technology-Based Phosphorus Effluent Limits (TBPEL) and other potential future effluent limits for nutrients.

     North Davis Sewer District’s (NDSD) mission is to meet and/or exceed regulatory requirements and protect the water quality of receiving water bodies. This project explores alternatives that may be more beneficial than a No-Action Alternative.

  1. Maximizes the benefit of NDSD’s effluent to Great Salt Lake (GSL) and the public.

    NDSD seeks to invest in alternatives that (1) improve the water quality of Farmington Bay and (2) maximize the probability that NDSD’s effluent will continue to flow into GSL into the future.

  2. Guides capital investment.

    NDSD does not want to make short-sighted or unnecessary WRF improvements that need to be torn out, abandoned, and replaced because of new, more stringent nutrient regulatory requirements in the near future.


NDSD initiated the development of a Nutrient Management Master Plan study in 2017 to define an effective and efficient strategy to meet the TBPEL and other future potential regulatory requirements. The traditional approach to facility planning is often driven by regulations, with planners typically addressing uncertainty in future regulations by defining the most likely and conservative requirements. Planning for treatment facilities is then done to meet those requirements over the anticipated facility lifespan. NDSD’s initial planning identified short-term WRF improvements to meet current TBPEL requirements and a new WRF as a means to meet anticipated new site-specific nutrient water quality criteria, possible TP total maximum daily loads (TMDL), and/or potentially new, more stringent statewide technology-based effluent limits intended to protect the water quality of Farmington Bay and GSL.

NDSD planners determined that enhanced water quality in combination with increasing demand for water resources will likely increase the value of a new WRF effluent in the marketplace and lead others to reuse it for secondary or even primary drinking water uses. Simply stated, higher water quality paid for by NDSD makes the effluent more attractive to other water purveyors who now have less to invest themselves for its use. Although reuse would eliminate all of NDSD’s nutrient load to Farmington Bay, it may also eliminate the WRF’s effluent to Farmington Bay and GSL. A reduction of inflows to GSL could then further exacerbate already observed detrimental changes in GSL’s ecosystem due to declining water levels, such as water quality, shoreline habitat, Gilbert Bay nutrient levels, etc. These outcomes are inconsistent with the objectives of NDSD and GSL’s stakeholders. It is important to keep water flowing to GSL. NDSD worked with DWQ and GSL stakeholders to investigate alternatives to meeting the TBPEL that both meet water quality regulations and increase the probability of maintaining its flow into GSL.



Learn More About NDSD


Antelope Island Resources