4.3 Water Quality

Goal 3 - Water Quality

Preserve, maintain and improve aesthetic, physical, chemical and biological composition of surface waters and groundwater within the District.

Discussion

The HHPLS used an extensive public input process to establish water quality goals for the primary receiving waters in the District, focusing primarily on identifying target total phosphorus concentrations.   This plan identifies those plus additional goals related to water quality.  This plan sets forth a set of actions the District will undertake to reduce pollutant loading in the subwatershed and achieve water quality goals.  The achievement of these water quality goals is not only necessary to meet state and federal water quality requirements and to prevent future TMDLs, but also to meet this plan’s ecological integrity goals. 

Desired Outcomes: Achievement of in-lake nutrient concentration goals through achievement of nutrient loading reductions

Metrics:

  • In-lake nutrient concentrations/Trophic State Index Scores (TSI) for Long Lake and Tanager Lake
  • Nutrient loading goals (pounds) for Long Lake, Long Lake Creek and Tanager Lake

Goal 3.1 - Long Lake

Achieve and maintain an interim in-lake total phosphorus concentration goal of 50 μg/L in Long Lake.

Actions

  1. Conduct a diagnostic study of internal lake phosphorus loading, including aquatic vegetation and fish surveys and updating the XPSWMM and P-load models to account for the final Highway 12 design, prepare a feasibility study, and implement improvements to reduce internal loading by at least 70 percent.
  2. Amend existing or establish new District rules requiring greater than 50 percent phosphorus removal on new permitted developments within the Long Lake subwatershed
  3. Implement improvement projects to the Park Ponds to increase treatment capacity and effectiveness.
  4. Require LGUs to reduce phosphorus loading from developed and agricultural uses upstream of Long Lake by a minimum of 129 pounds per year within 10 years.
    1. Provide education and training opportunities, technical and planning assistance for property owners and LGUs on methods to reduce phosphorus and sediment loading by incorporating BMPs into landscaping, agriculture, infrastructure maintenance, and reconstruction.
  5. Provide assistance to LGUs and developers to foster low impact development and redevelopment that minimizes new phosphorus and sediment loading.
    1. Develop and distribute model ordinances and design standards that incorporate low impact design principles.
    2. Sponsor educational opportunities for LGU staff, developers, elected and appointed officials and other interested parties to provide practical information and opportunities for sharing experiences.
  6. Promote the general application of BMPs across the subwatershed.
    1. Consider developing a small grant program to provide financial assistance to property owners desiring to retrofit their property with BMPs to reduce phosphorus and sediment loading.
  7. Continue regular water quality monitoring in Long Lake to assess progress toward achieving the in-lake phosphorus goal. 

Goal 3.2 - Long Lake

Achieve no degradation of existing water quality in Mooney, Wolsfeld, and Holy Name Lakes.

Actions

  1. Obtain baseline water quality data for Mooney, Wolsfeld, and Holy Name Lakes and update every three to five years.
  2. Work cooperatively with the DNR and other parties to identify and address potential sources of pollutant and sediment loading into Wolsfeld Lake from the Wolsfeld Woods Scientific and Natural Area.

Goal 3.3 - Long Lake

Achieve in-lake total phosphorus concentration goal of 70 μg/L in Tanager Lake.

Actions

  1. Conduct a diagnostic study of the source of the phosphorus load increase from upstream to downstream in Long Lake Creek and potential impacts on Tanager Lake, and identify options for reducing phosphorus in Tanager Lake.
  2. Construct detention ponds in LLC-48 and LLC-51 to reduce phosphorus loading to Tanager Lake from those subwatersheds by 50 percent.
  3. Require LGUs to reduce phosphorus loading from developed and agricultural uses upstream of Tanager Lake by a minimum of 38 pounds per year within 10 years.
    1. Provide education and training opportunities, technical and planning assistance for property owners and LGUs on methods to reduce phosphorus and sediment loading by incorporating BMPs into landscaping, agriculture, infrastructure maintenance, and reconstruction.

Goal 3.4 - Long Lake

Achieve and maintain other state lake water quality standards including >1.4 m Secchi clarity and 14 ug/L chl-a, in Long Lake and Tanager Lake.

Actions

  1. Achieve and maintain in-lake total phosphorus goals.
  2. Manage aquatic vegetation in accordance with a vegetation management plan that takes into account water clarity goals.

Goal 3.5 - Long Lake

Achieve and maintain state water quality standards in Long Lake Creek and minimize pollutant loading contribution to Browns Bay.

Actions

  1. Achieve Long and Tanager Lakes in-lake total phosphorus concentration goals.
  2. Inspect erosion-prone areas of Long Lake Creek at least annually to identify any new areas of erosion, and the entire creek every five years.
  3. Work cooperatively with the City of Orono to spot repair identified erosion locations in Long Lake Creek and develop strategies to prevent future erosion and sediment transport.
  4. Complete any creek improvement projects identified in the Tanager Lake diagnostic study.
  5. Continue to monitor water quality in Long Lake Creek.
  6. Develop a water quality index which encompasses the District’s broader definition of water quality.