The National Park Service (NPS) organized more than 270 parks with important natural resources into 32 ecoregional networks to conduct Inventory and Monitoring (I&M) activities for assessment of natural resources within park units. The Missouri National Recreational River (NRR) is among the 13 parks in the NPS Northern Great Plain Network (NGPN). Park managers and NGPN staff identified surface water resources as a high priority vital sign to monitor in park units. The objectives for the Missouri NRR water quality sampling design are to (1) assess the current status and long-term trends of select water quality parameters; and (2) document trends in streamflow at high-priority stream systems. Due to the large size of the Missouri River main stem, the NGPN water quality design for the Missouri NRR focuses on wadeable tributaries within the park unit. To correlate with the NGPN water quality protocols, monitoring of the Missouri NRR consists of measurement of field core parameters including dissolved oxygen, pH, specific conductance, and temperature; and streamflow. The purpose of this document is to discuss factors examined for selection of water quality monitoring on segments of the Missouri River tributaries within the Missouri NRR.

Awareness of the complex history of the Missouri NRR aids in the current understanding and direction for designing a monitoring plan. Historical and current monitoring data from agencies and entities were examined to assess potential NGPN monitoring sites. In addition, the U.S. Environmental Protection Agency 303(d) list was examined for the impaired segments on tributaries to the Missouri River main stem. Because major tributaries integrate water quality effects from complex combinations of land use and environmental settings within contributing areas, a 20-mile buffer of the Missouri NRR was used to establish environmental settings that may impact the water quality of tributaries that feed the Missouri River main stem. For selection of monitoring sites, anthropogenic and natural influences to water quality were assessed for Missouri NRR tributaries. Factors that were examined include the size and contributions of tributaries within watersheds to the main stem; population density; and land use such as urban development and agricultural practices including concentrated animal feeding operations. Based on examination of these data in addition to the park’s legislation and management considerations, two sites were selected for monitoring water quality on Missouri NRR tributaries for the ice-free season (mid-May to mid-October) on a rotational basis every third year. Bow Creek at St. James was selected for water quality monitoring based on lack of long-term water quality monitoring, current recreational use, and proximity of the tributary to intense agricultural practices. In addition, land within the Bow Creek watershed is owned by the NPS. The Niobrara River at Verdel was selected for monitoring due to high use for public recreational activities, adjacent agricultural land use, and documented impairments for designated beneficial uses. Both sites will have access to real-time streamgages that will aid in a greater understanding of water quality.