KANSAS-LOWER REPUBLICAN BASIN TOTAL MAXIMUM DAILY LOAD Waterbody/Assessment Unit: Big Blue River Watershed Water Quality Impairment: Total Phosphorus and pH 1. INTRODUCTION AND PROBLEM IDENTIFICATION Subbasin: Lower Big Blue, Lower Little Blue Counties: Marshall, Washington HUC8: 10270205 HUC10 (12): 01 (03, 04) 02 (01, 02, 03, 04) 05 (01, 02, 03) HUC8: 10270207 HUC10 (12): 06 (06) Ecoregion: Smoky Hills (27a), Flint Hills (28a), and Loess and Glacial Drift Hills (47i) Drainage Are a: Approximately 383 square miles (mi2) Water Quality Limited Segments Covered Under TMDL (designated uses for main stem and tributary segments are detailed in Table 1): Main Stem Segment Tributaries Tributaries HUC8: 10270205 Big Blue R (21) Deer Cr (36) Scotch Cr (38) Bommer Cr (40) Elm Cr, North (41) Mission Cr (22) Murdock Cr (42) Big Blue R (20) Horseshoe Cr (26) Raemer Cr (33) Indian Cr (37) Meadow Cr (34) Little Indian Cr (35) Big Blue R (18) Dutch Cr (44) Hop Cr (43) Spring Cr (19) Schell Cr (45) Lily Cr (39) Big Blue R (17) Elm Cr (46) HUC8: 10270207 Fawn Cr (45) 1 Table 1. Designated uses for main stem and tributary segments in the watershed (Kansas Department of Health and Environment, 2013). Stream Segment Expected Contact Domestic Food Ground Industrial Irrigation Livestock # Aquatic Recreation Supply Procurement Water Water Use Use Watering Life Recharge Use HUC8: 10270205 Big Blue R 17 E B X X X X X X Elm Cr 46 E b X X X X X X Big Blue R 18 E B X X X X X X Dutch Cr 44 E b O O O O O O Hop Cr 43 E b O X X O X X Spring Cr 19 E B X X X X X X Schell Cr 45 E b X X X X X X Lily Cr 39 E b X X X X X X Big Blue R 20 E C X X X X X X Deer Cr 36 E b X X X X X X Scotch Cr 38 E b O O O O O X Bommer Cr 40 E b X O X X X X Big Blue R 21 E C X X X X X X Mission Cr 22 E C X X X X X X Murdock Cr 42 E b X O X X X X Horseshoe Cr 26 E C X X X X X X Raemer Cr 33 E b X X X X X X Indian Cr 37 E b X X X X X X Meadow Cr 34 E b X X X X X X Little Indian Cr 35 E b X X X X X X Elm Cr, North 41 S b X X X X X X HUC8: 10270207 Fawn Cr 45 E b X O X X X X X=use is designated; O=use is not designated; E=Expected aquatic life; S=Special aquatic life; B, C=Primary contact recreation; b=Secondary contact recreation Impaired Use: Expected aquatic life, contact recreation, domestic water supply 303(d) Listings: Kansas stream segments monitored by station SC731 (Figure 1), North Elm Creek near Oketo, are cited as impaired by total phosphorus (TP) in 2008, 2010, 2012, 2014, 2016, and 2018. Kansas stream segments monitored by station SC233, Big Blue River near Oketo, are cited as impaired by: TP in 2008, 2010, 2012, 2014, 2016, and 2018; pH in 2002, 2004, 2008, 2010, 2012, 2014, 2016, and 2018; and biology in 2004, 2008, 2010, 2012, 2014, 2016, and 2018. Kansas stream segments monitored by station SC717, Horseshoe Creek near Marysville, are cited as impaired by TP in 2008, 2010, 2012, 2014, 2016, and 2018. Kansas stream segments monitored by station SC240, Big Blue River near Blue Rapids, are cited as impaired by TP in 2008, 2010, 2012, 2014, 2016, and 2018 and by pH in 2004, 2008, 2010, 2012, 2014, 2016, and 2018. 2 Figure 1. Map of contributing area for KDHE stream chemistry stations SC731, SC233, SC717, and SC240. 3 Water Quality Criteria: Nutrients -- Narrative: The introduction of plant nutrients into streams, lakes, or wetlands from artificial sources shall be controlled to prevent the accelerated succession or replacement of aquatic biota or the production of undesirable quantities or kinds of aquatic life (K.A.R. 28-16- 28e(d)(2)(A)). The introduction of plant nutrients into surface waters designated for primary or secondary contact recreational use shall be controlled to prevent the development of objectionable concentrations of algae or algal by-products or nuisance growths of submersed, floating, or emergent aquatic vegetation (K.A.R. 28-16-28e(d)(7)(A)). The introduction of plant nutrient into surface waters designated for domestic water supply use shall be controlled to prevent interference with the production of drinking water (K.A.R. 28-16- 28e(d)(3)(D)). Taste-producing and odor-producing substances of artificial origin shall not occur in surface waters at concentrations that interfere with the production of potable water by conventional water treatment processes, that impart an unpalatable flavor to edible aquatic or semiaquatic life or terrestrial wildlife, or that result in noticeable odors in the vicinity of surface waters (K.A.R. 28-16-28e(b)(7)). Dissolved Oxygen -- Numeric: The concentration of dissolved oxygen in surface waters shall not be lowered by the influence of artificial sources of pollution. The Dissolved Oxygen criterion is 5 mg/L (K.A.R. 28-16-28e(e), Table 1g). pH -- Numeric: Artificial sources of pollution shall not cause the pH of any surface water outside of a zone of initial dilution to be below 6.5 and above 8.5 (K.A.R. 28-16-28e(e), Table 1g). 2. CURRENT WATER QUALITY CONDITIONS AND DESIRED ENDPOINT Level of Support for Designated Uses under the 2018 303(d) List: Phosphorus levels in Big Blue River near Oketo (SC233), Big Blue River near Blue Rapids (SC240), Horseshoe Creek near Marysville (SC717), and North Elm Creek near Oketo (SC731) are consistently high. Excessive nutrients are not being controlled and are thus impairing aquatic life, domestic water supply, and contact recreation uses. The ultimate endpoint of this Total Maximum Daily Load (TMDL) will be to achieve the Kansas Surface Water Quality Standards by eliminating excessive primary productivity and impairment to aquatic life, recreation, and domestic water supply associated with excessive phosphorus. Station Location and Period of Record: Stream Chemistry (SC) Monitoring Station: SC731: Active rotational station on North Elm Creek near Oketo, located on a county road bridge 1.75 miles north of Oketo. Sampled quarterly every four years in the period of record from April 16, 2001 to December 4, 2017. 4 SC233: Active permanent station on Big Blue River near Oketo, located on a K-233 highway bridge 0.5 miles south and 0.5 mile west of Oketo. Sampled quarterly in the period of record from March 13, 1990 to October 15, 2018. SC717: Active rotational station on Horseshoe Creek near Marysville, located on a U.S. 77 highway bridge 1.2 miles west and 3.75 miles north of Marysville. Sampled quarterly every four years in the period of record from January 26, 1998 to December 4, 2017. SC240: Active permanent station on Big Blue River near Blue Rapids, located on a U.S. 77 highway bridge 1.4 miles east of Blue Rapids. Sampled quarterly in the period of record from March 13, 1990 to October 15, 2018. Stream Biology (SB) Monitoring Stations: SB233: Active station on Big Blue River 1 mile west of Oketo. Period of record: April 3, 1990 to June 27, 2017. SB240: Active station on Big Blue River on U.S. Highway 77, 1.4 miles northeast of Blue Rapids. Period of record: July 17, 2013 to August 16, 2016. SB374: Inactive station on North Elm Creek at a county road bridge 2 miles east and 2.5 miles North of Oketo. Period of record: July 13, 1999 to October 17, 2000. SB475: Inactive station on Horseshoe Creek on a county road bridge 2.1 miles north of Herkimer. Period of record: October 6, 2010 to October 13, 2015. SB476: Inactive station on Spring Creek on a county road bridge 0.6 miles south of Marysville. Period of record: October 6, 2010 to October 13, 2015. Stream Probabilistic (SP) Monitoring Stations: SP826: North Elm Creek. Period of record: 2006, 2008, and 2011. SPA066: Horseshoe Creek. Period of record: 2006. SPB514: Indian Creek. Period of record: 2016. SPB172: Spring Creek. Period of record: 2012. SPB642: Schell Creek. Period of record: 2017. SPA285: Dutch Creek. Period of record: 2008 and 2017. SPB173: Fawn Creek. Period of record: 2012. Streamflow Gage: U.S. Geological Survey 06882510: Big Blue River at Marysville. Period of record: January 1, 1990 to December 31, 2018. U.S. Geological Survey 06814000: Turkey Creek near Seneca. Period of record: January 1, 1990 to December 31, 2018. Hydrology: Streamflow conditions were developed using U.S. Geological Survey (USGS) streamgage data from the Big Blue River at Marysville (06882510) and Turkey Creek near Seneca (06814000). Total flow at KDHE stream chemistry (SC) stations SC233 and SC240 is based on the watershed ratio between values from Big Blue River segments located in Marshall County (as determined by USGS in Perry et. al., 2004) and the contributing drainage area of USGS gage 06882510, including flow originating in Nebraska. The calculations for the discreet drainage areas within Kansas measured at SC233 and SC240 applied the ratio of the watershed size of the KDHE SC station to the area of the USGS gage.