2017 - NFCRWD CD5, CD29 & CD37 Subwatershed Assessment

     There is one lake and three streams in the North Fork Crow River Watershed District (NFCRWD) impaired by excess nutrients and impaired biotic communities. HSPF and unit area load models completed for the TMDL/WRAPS identified large areas and subwatersheds that have the potential to contribute high pollutant loads to the streams and lakes throughout the watershed. These models were built at large scales and are therefore not sufficient to pinpoint to the field level where BMPs would be most effective. The NFCRWD Subwatershed Assessment study evaluates three high loading subwatershed catchments in the North Fork Crow River Watershed. This study will use finer-scaled models (PTMApp and ACPF) and additional subwatershed analyses to develop prioritized maps and an itemized list of potential projects and practices with cost/benefit analyses, expected load reductions, and public outreach.

     The Rice Lake TMDL study and the North Fork Crow WRAPS study set forth required pollutant load reductions for one nutrient impaired lake (Rice Lake) and three stream reaches impaired with fish and/or macroinvertebrate communities. Recent monitoring by the NFCRWD indicates high levels of bacteria in several streams throughout the watershed which may lead to future impairments. Additionally, a Stressor Identification study for the stream impairments suggest that deposited sediment contributes to the stream biotic impairments. HSPF modeling completed for the TMDL and WRAPS studies identified several high potential sediment and phosphorus loading subwatersheds within the North Fork Crow River Watershed. The HSPF model was built at a relatively large scale and is not capable of pinpointing exactly which fields and locations should be targeted for BMPs. The NFCRWD Subwatershed Assessment will evaluate watersheds of three county ditches in Stearns County (CD 5, CD 29, CD 37) that have been identified as having very high potential to contribute sediment, phosphorus, and bacteria loads. These ditches drain directly to the North Fork Crow River and are located within the Rice Lake watershed, which requires a very large watershed phosphorus load reduction of over 26,000 pounds per year (53% reduction). This subwatershed assessment will use fine-scale prioritization models, PTMApp and ACPF, that will provide the NFCRWD, Stearns SWCD and other local resource managers a prioritized list of potential projects and practices and a cost/benefit analysis so local stakeholders can begin engaging private landowners and implementing BMPs.

     The NFCRWD is currently moving toward using subwatershed assessments and stormwater retrofit assessments as the new norm in identifying high loading areas within their watershed, and priority areas for implementing BMPs. The NFCRWD plans to incorporate the BMP planning maps and other results of this study (and future assessments) into their watershed management plan. The NFCRWD will also use results of this study as a reference tool in applying for future grants to construct and implement the identified BMPs. Through the project meeting and public outreach process, the TAG will help identify appropriate implementation actions, and focus their technical expertise and resources on high-loading priority areas in the three subwatersheds. The TAG will reach out to local landowners and small focus groups to present results, raise awareness, build trust and “buy-in”, and to establish a new norm for BMP planning. The anticipated outcome is a new norm/framework for BMP planning, along with an increase in landowners undertaking voluntary practices and demonstrating to their neighbors that the BMPs are cost effective and practical.