The City of Columbus Division of Sewers and Drains (DOSD) and MBI announce the release of a second major report on the historical ecological success story of Central Ohio’s two major rivers. This report, entitled Biological and Water Quality Assessment of the Middle Scioto River, Lower Olentangy River, and Lower Olentangy Tributaries 2022. Delaware, Franklin, and Pickaway Counties, Ohio (MBI Technical Report MBI 2023-12-12), is another major milestone in the management and assessment of rivers and streams as affected by 50 years of the implementation of the Clean Water Act (CWA) by private, local, state, and federal agencies and organizations. The scope of the 2022 biological and water quality assessment, included the Scioto River mainstem between Griggs Dam in Columbus to Canal Park in Circleville, the Olentangy River mainstem from Powell Rd. to the mouth in downtown Columbus, and nine Olentangy River tributaries in Columbus, two of which are part of Blueprint Columbus

The City of Columbus Division of Sewers and Drains (DOSD) sponsored the July-October 2022 biological and water quality assessment of the Olentangy and Scioto Rivers. The assessment included:

  • 25 sites on the Scioto River mainstem between Griggs Dam in Columbus to Canal Park just below Circleville and a single site on Big Walnut Creek;
  • 11 sites on the Olentangy River mainstem in southern Delaware and Franklin Counties; and,
  • 12 sites located across nine (9) Olentangy River tributary subwatersheds, three that are directly related to Blueprint Columbus (Adena Brook, Beechwold Run, Wahalla Hollow) and the others related to the Wet Weather Management Plan and MS4 stormwater permitting and local watershed group interests.

Consistent with prior surveys of this area dating back to 1979, the sampling included water chemistry, sediment chemistry, habitat, and biological assemblages. Chemical analyses were conducted for 24 laboratory analytes and four field parameters in water and seven (7) heavy metals and multiple organic chemical compounds in sediments. E. coli bacteria counts were determined to assess the status of the Primary Contact Recreational (PCR) use. Parameters consistent with the proposed Ohio EPA nutrient effects assessment methodology were also collected including two forms of chlorophyll a and continuous dissolved oxygen (D.O.), temperature, pH, and conductivity in the Scioto and Olentangy River mainstems. Habitat quality was assessed with the Qualitative Habitat Evaluation Index (QHEI) and the biological assemblages included fish and macroinvertebrates consistent with Ohio EPA methods and the biological criteria for assessing the status of aquatic life use designations per the Ohio Water Quality Standards (WQS) (OAC 3745-1-07) at all sites. The sampling was performed under an approved Level 3 study plan per the Ohio Credible Data Law (ORC 6111.5) and Regulations (OAC 3745-4). The report is organized by the two distinct river mainstem reaches and tributary subwatersheds for the 2020 study area – the Scioto River mainstem, the Olentangy River mainstem, and the Olentangy Tributaries. With the exception of portions of the Summary and Conclusions, Introduction, Methods, and Study Area, each Results and Discussion section of the report is written as a stand-alone reporting of the results, thus certain descriptions of pollutants and indicators are redundant between the three major sections.


Chris Yoder