Citation:

McManus, M., C. Nietch, Matthew Heberling, AND L. Gains-Germain. Decreasing Trends in Total Suspended Solids and Cumulative Effects of Nonpoint Source Projects in the Cuyahoga River Watershed, OH. JOURNAL OF GREAT LAKES RESEARCH. International Association for Great Lakes Research, Ann Arbor, MI, 49(3):608-620, (2023). https://doi.org/10.1016/j.jglr.2023.03.011

Impact/Purpose:

The US EPA spends millions of dollars as part of its Section 319 program to help address state and local nonpoint source problems. States receiving grants report their annual progress in the Grants Reporting and Tracking System (GRTS). Using GRTS, we test if implementation of best management practices (BMPs) through the 319 program in the Cuyahoga River watershed is associated with an overall decreasing trend from 2000 to 2017 in the nonpoint source pollutant total suspended solids (TSS). A focus of the 319 projects was reduction in sedimentation-siltation loads. We identified 3 phases of implementation of 319 projects. Phase 1 corresponded to 2000-2004 in which 319 projects were ongoing, but none were completed. During Phase 1, no trend in Cuyahoga River TSS load occurred. Phase 2 was from 2005-2011 when six projects were completed, with the first three of those projects coordinated for dam modification or removal on the mainstem of the Cuyahoga River. During Phase 2, a strong decreasing trend in TSS load was observed. Phase 3 was from 2012-2017 when 13 projects were completed, with these projects were more distributed in the tributaries of the watershed, with several focused on urban runoff, in addition to a one-time dam modification removal project on the Little Cuyahoga River. During Phase 3, a modest decline in TSS was detected. The estimates of sedimentation-siltation load reductions from 319 projects were quite small relative to the TSS load in the Cuyahoga River. While a decreasing trend in a nonpoint source pollutant is a desirable water quality outcome, determining what contributed to that trend remain difficult.

Description:

Using the US EPA’s Grants Reporting and Tracking System (GRTS), we test if completion of best management practices (BMPs) through the Clean Water Act Section (§)319 National Nonpoint Source Program was associated with a decreasing trend in total suspended solids (TSS) load (metric tons/year). The study area chosen had 21 completed projects in the Cuyahoga River watershed in northeastern Ohio from 2000 to 2018. The §319 projects ranged from dam removal, floodplain/wetland restoration to stormwater projects. There was an overall decreasing trend in TSS loads. We identified three phases of project implementation and completion, where phase 1 had ongoing projects, but none completed (2000–2004). The steepest decrease in loads, identified as phase 2 (2005–2011), was associated with completion of low-head dam modification and removal projects on the mainstem of the Cuyahoga River. A likely decreasing trend was associated with projects completed in the tributaries, such as natural channel design restoration and stormwater green infrastructure (phase 3). Pairing sediment reduction estimates from projects with the river’s flow normalized TSS loading trend, we estimated that the §319 effort may account for a small fraction of the TSS load reduction. Other stream restoration projects (non-§319) have also been done in the Cuyahoga watershed by other organizations. However, trying to compile these other projects is challenging in larger watersheds having multiple municipalities, agencies, and nonprofits doing restoration without better coordinated record keeping and monitoring. While a decreasing trend in a pollutant load is a desirable water quality outcome, determining what contributed to that trend remains difficult.

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