Quality of surface water in Missouri, water year 2017

The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a network of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network. During water year 2017 (October 1, 2016, through September 30, 2017), data presented in this report were collected at 72 stations: 70 Ambient Water-Quality Monitoring Network stations and 2 U.S. Geological Survey National Stream Quality Assessment Network stations. Among the 72 stations in this report, 4 stations have data presented from additional sampling performed in cooperation with the U.S. Army Corps of Engineers. Summaries of the concentrations of dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, Escherichia coli bacteria, fecal coliform bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and selected pesticide compounds are presented. Most of the stations have been classified based on the physiographic province or primary land use in the watershed represented by the station. Some stations have been classified based on the unique hydrology of the waterbodies they monitor. A summary of hydrologic conditions in the State including peak streamflows, monthly mean streamflows, and 7-day low flows also are presented. Introduction The Missouri Department of Natural Resources (MDNR) is responsible for the implementation of the Federal Clean Water Act (33 U.S.C. §1251 et seq.) in Missouri. Section 305(b) of the Clean Water Act requires that each State develop a water-quality monitoring program and periodically report the status of its water quality (U.S. Environmental Protection Agency, 1997). Water-quality status is described in terms of the suitability of the water for various uses, such as drinking, fishing, swimming, and supporting aquatic life; these uses formally were defined as “designated uses” in State and Federal regulations. Section 303(d) of the Clean Water Act requires States to identify impaired waters and determine the total maximum daily loads (TMDLs) of pollutants that can be present in these waters and still meet applicable water-quality standards for their designated uses (U.S. Environmental Protection Agency, 2018). A TMDL addresses a single pollutant for each waterbody. Missouri has an area of about 69,000 square miles and an estimated population of 6.09 million people (U.S. Census Bureau, 2016). Within Missouri, 115,772 miles (mi) of classified streams support a variety of uses including wildlife, recreation, agriculture, industry, transportation, and public utilities, but only 24,761 mi (or about 21 percent) were monitored, evaluated, and assessed in the State’s most recent waterquality report (Missouri Department of Natural Resources, 2016a). Of these assessed stream miles, an estimated 5,307 mi fully support the designated uses, and an estimated 5,549 mi are impaired by various physical changes or chemical contaminants to the point that criteria for at least one of the designated uses no longer can be met (Missouri Department of Natural Resources, 2016a). The purpose of this report is to summarize surface-water quality data collected for the MDNR–U.S. Geological Survey (USGS) cooperative Ambient Water-Quality Monitoring Network (AWQMN) for water year 2017. The annual summary of select constituents provides MDNR with current information to assess the quality of surface water within the State and ensure the objectives of the AWQMN are being met. This report is one in a series of annual summaries (Otero-Benitez and Davis, 2009a, 2009b; Barr, 2010, 2011, 2013, 2014, 2015; Barr and Schneider, 2014; Barr and Heimann, 2016; Barr and Bartels, 2018). Data on the physical characteristics and waterquality constituents in samples collected during the 2017 water year are presented in figures and tables for 72 surface-water stations located throughout the State. The Ambient Water-Quality Monitoring Network The USGS, in cooperation with the MDNR, collects surface-water quality data pertaining to water resources in Missouri each water year (October 1 through September 30). These data, stored and maintained in the USGS National Water Information System (NWIS) database (U.S. Geological Survey, 2017), are collected as part of the Missouri AWQMN. The data collected for the AQWMN constitute a permanent source of accessible, accurate, impartial, and timely information for 2 Quality of Surface Water in Missouri, Water Year 2017 developing an enhanced understanding of the State’s water resources. Historical surface-water quality data were published annually in the Water-Data Report series from water years 1964 through 2005 (U.S. Geological Survey, 1964–2005). Published data for the 2006 through 2010 water years can be accessed at https://wdr.water.usgs.gov/ (U.S. Geological Survey, 2006b–2010). Beginning in water year 2011, discrete water-quality data were no longer published annually but can be accessed in the NWIS database (U.S. Geological Survey, 2017). The objectives of the AWQMN are to (1) obtain data on the quality and quantity of surface water within the State; (2) provide a database of historical water-quality information that can be used by the State planning and management agencies to make informed decisions about anthropogenic effects (such as agriculture, mining, and urban) on the State’s surface waters; and (3) provide for consistent methodology in data collection, laboratory analysis, and data reporting. Constituent concentration data from the AWQMN have been used to determine statewide water-quality status and long-term trends (Barr and Davis, 2010) to meet information needs of State agencies involved in water-quality planning and management. The data collected also provide support for the design, implementation, and evaluation of preventive and remediation programs. The MDNR and the USGS established a fixed-station AWQMN in 1964 with 18 stations, 5 of which are being sampled currently (2018). The number of stations within the AWQMN has varied since its inception because of changes in the State’s needs. During water year 2017, the AWQMN program consisted of 70 stations (69 primary stations and 1 alternate station). Alternate sampling stations have been established at streamflow-gaging stations near some primary AWQMN stations, and one such station, Drywood Creek near Deerfield, Missouri (06917680), was sampled in September 2017 because of dry conditions at East Drywood Creek at Prairie State Park, Mo. (06917630). Sampling frequency at each station is determined by several factors, including drainage basin size, potential effects from anthropogenic activities (such as agriculture, mining, and urban), history of chemical change, need for annual data, and cost. Each of the streams in the AWQMN is classified for one or more designated uses. For specific information on the designated uses applicable to the streams sampled in the AWQMN, refer to Missouri Department of Natural Resources (2016a; 2016b). The unique eight-digit number used by the USGS to identify each surface-water station is assigned when a station is first established. The complete eight-digit number for each station includes a two-digit prefix that designates the primary river system (05 is the upper Mississippi River, 06 is the Missouri River, and 07 is the lower Mississippi River) plus a six-digit downstream-order number; for example, the station number 05587455 indicates the station is in the upper Mississippi River system (05), and the remaining six digits (587455) locate the station in downstream order. In this system, the station numbers increase downstream along the main stem. A station on a tributary that enters between two main stem stations is assigned a station number between them. Constituents collected within the AWQMN have been established by the MDNR based on their data needs at each station. Samples were collected by USGS personnel; collection methods and techniques followed USGS protocol (U.S. Geological Survey, 2006a). Onsite measurements of dissolved oxygen, specific conductance, and water temperature were collected at each station according to procedures described in Wilde (variously dated). Water samples were collected and processed for fecal indicator bacteria [Escherichia coli (E. coli) and fecal coliform] densities using the membrane filtration procedure described in Myers and others (2014). Methods used by the USGS for collecting and processing representative samples for nutrients, primary chemical constituents, trace elements, suspended solids, suspended sediment, and pesticide analyses are presented in detail in U.S. Geological Survey (2006a), Guy (1969), Wilde and others (2004), and Sandstrom and Wilde (2014). All laboratory analyses were done by the USGS National Water Quality Laboratory (NWQL) in Lakewood, Colorado, according to procedures described in Garbarino and others (2006), Fishman (1993), Patton and Kryskalla (2011), Patton and Truitt (1992), Sandstrom and others (2001 and 2015), and Zaugg and others (1995). Suspended-sediment concentrations were computed according to procedures described in Guy (1969). In addition to the surface-water quality data collected from the 70 stations that form the AWQMN, selected data collected as part of other cooperative efforts are included in this report to help summarize water-quality conditions across the State. Water samples also are collected by the USGS at two USGS National Stream Quality Assessment Network (NASQAN; a national water-quality sampling network operated by the USGS, see https://cida.usgs.gov/quality/rivers/ home) stations. Sediment samples collected at four USGS streamflow-gaging stations are presented in this report. These samples are collected as part of a larger monitoring effort in cooperation with the U.S. Army Corps of Engineers. The suspended-sediment concentration data in this report ar