Up a Creek with a Paddle: Performance of a Visual Stream Assessment in a Non-Wadeable River

IntroductionAs part of the new National Pollutant Discharge Elimination System (NPDES) MS4 permit regulations for Tennessee, all impaired waterbodies within the city limits are required to have visual impairment inventories performed within the 5-year permit cycle. CDM Smith performed a visual stream assessment for a watershed in West Tennessee within the urbanized portion of the waterbody. The waterbody also included several sections that are impaired for pathogens, as listed on the State's 2010 303(d) list. As part of the pathogen total maximum daily load (TMDL) for the waterbody, a visual stream impairment inventory is also required to be performed within 5 years of the TMDL issuance.The ScopeA unique aspect of this project is the fact that the waterbody is a non-wadeable stream. Several protocols already exist for the assessment of wadeable streams and creeks; however, the comprehensive development of a non-wadeable protocol did not exist for the state of Tennessee or the city. CDM Smith worked with a municipality to develop the protocol for the waterbody assessment, as well as to develop a standard for other assessments performed on the major rivers within the municipality.The SolutionCDM Smith consulted several guidance documents in development of the protocol that used a combination of both wadeable and non-wadeable streams. This manuscript will cover the guidance documents used and the information that was obtained from each of these for the specific impairments observed in the West Tennessee watershed. The protocol was developed for evaluation of the watershed based on land uses observed within the city; potential locations for pathogen impairment; siltation and habitat impairment parameters; and logical, logistical, access points to the river.Based on a review of the guidance documents, CDM Smith created a series of field data sheets to be used during the evaluation of the river. These data sheets were created to quickly assess and obtain qualitative data observations for characteristics of the river. Data relating to pathogens and siltation and habitat impairments were listed to be gathered during the assessment to develop criteria for future trending of the watershed.Field WorkThe visual assessment was performed through canoe access within the river to allow for appropriate investigation of the banks with follow-up via foot reconnaissance to verify potential areas of concern and collect required additional data. After the assessment was completed, the collected data was compiled into an evaluation report to assess the overall health of the river and watershed and provide a baseline for continuing assessment in the future. The primary objectives of the assessment were to identify and prioritize stream impairment sources, as well as, identify potential best management practices (BMPs) and corrective measures to remedy the priority areas.ConclusionThis presentation will describe the protocol development, coordination with the Tennessee Department of Environment and Conservation (TDEC) and other regulatory agencies, methods and logistics for performing a successful visual stream assessment in a non-wadeable river, examples of potential data produced from the assessment, and methodology for compiling all of the data and summarizing the findings into a useable format for future improvements and corrective measures.There is increasing development of TMDLs and requirements for performance of visual stream assessments on all TMDLs developed for pathogen and siltation and habitat alteration. This manuscript will provide an overview and specific example of a successful visual assessment along with some lessons learned from our experiences.