Little Arkansas River from Alta Mills to Valley Center Water Quality Impairment: Total Phosphorous and Dissolved Oxygen

LOWER ARKANSAS RIVER BASIN TOTAL MAXIMUM DAILY LOAD

Waterbody: Little Arkansas River from Alta Mills to Valley Center Water Quality Impairment: Total Phosphorous and Dissolved Oxygen

1. INTRODUCTION

Subbasin: Little Arkansas Ecoregions: Central Great Plains (27): Great Bend Sand Prairie (c) and Wellington-McPherson Lowland (d)

Counties: Harvey (HV), Marion (MN), McPherson (MP), Reno (RN), Rice (RC), and Sedgwick (SG)

Drainage Area: 1039.6 square miles (mi2)

HUC8: 11030012 HUC10 (12): 01 (01, 02, 03, 04, 05, 06, 07) 02 (01, 02, 03, 09) 03 (01, 02, 03, 04, 05, 06, 07) 04 (01, 02, 03, 04, 07, 08) 05 (02)

Water Quality Limited Segments (Table 1; Figure 1)

Table 1. Main stem and tributary water quality limited segments in the Little Arkansas River Watershed. Main Stem Tributary Tributary of Tributary HUC8 11030012 Horse Cr (19) – Salt Cr (21) – Little Arkansas R (14) Dry Cr (22) – Lone Tree Cr (20) – Sand Cr (23) – Little Arkansas R (10) Black Kettle Cr (368) – Little Arkansas R (9) Kisiwa Cr (15) – Emma Cr, Middle (7) Little Arkansas R (5) Emma Cr (6) Emma Cr, West (8) Little Arkansas R (3) – – Gooseberry Cr (17) Little Arkansas R (1) Jester Cr (2) Jester Cr, W Fk (18) Jester Cr, E Fk (9002) Definition: – - No tributary.

Figure 1. Map of water quality impaired segments and contributing areas for Kansas Department of Health and Environment stream chemistry (SC) stations, as well as ancillary water quality stations.

Designated Uses by Segment (Table 2)

Table 2. Designated uses for main stem and tributary segments for the Little Arkansas River Watershed (Kansas Surface Water Register, 2013). Food Ground- Live- Aquatic Contact Domestic Stream Segment Procure- water Industrial Irrigation stock Life Recreation Supply ment Recharge Watering HUC8: 11030012 Little Arkansas R 14 E B Y Y Y Y Y Y Horse Cr 19 E b Y Y Y Y Y Y Salt Cr 21 E b N Y N N N N Dry Cr 22 E b N Y Y N N Y Lone Tree Cr 20 E b N Y Y N Y Y Sand Cr 23 E C N Y Y N Y Y Little Arkansas R 10 E C Y Y Y Y Y Y

Food Ground- Live- Aquatic Contact Domestic Stream Segment Procure- water Industrial Irrigation stock Life Recreation Supply ment Recharge Watering HUC8: 11030012 Black Kettle Cr 368 E B Y Y Y Y Y Y Little Arkansas R 9 E C Y Y Y Y Y Y Kisiwa Cr 15 E b Y Y Y Y Y Y Little Arkansas R 5 E C Y Y Y Y Y Y Emma Cr 6 E b Y Y Y Y Y Y Emma Cr, Middle 7 E B Y Y Y Y Y Y Emma Cr, West 8 E C Y Y Y Y Y Y Little Arkansas R 3 E C Y Y Y Y Y Y Little Arkansas R 1 E B Y Y Y Y Y Y Jester Cr 2 E C Y Y Y Y Y Y Gooseberry Cr 17 E b N Y N Y N N Jester Cr, W Fk 18 E C N Y N N N Y Jester Cr, E Fk 9002 E C Y Y Y Y Y Y Definitions: E - Expected aquatic life use water; B, C - Primary contact recreation stream; Y - Referenced stream segment is assigned the indicated designated use; b - Secondary contact recreation stream; N - Referenced stream segment does not support the indicated designated use.

Impaired Uses: Expected aquatic life, contact recreation, and domestic water supply

303(d) Listings for Total Phosphorus, Biology, and Dissolved Oxygen Little Arkansas River at Alta Mills (SC246) Total phosphorus, category 5: 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Biology, category 4a: 2002, 2004, 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Black Kettle Creek near Halstead (SC705) Total phosphorus, category 5: 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Biology, category 4a: 2002, 2004, 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Dissolved Oxygen, category 5: 2004, 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Kisiwa Creek near Halstead (SC703) Total phosphorus, category 5: 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Biology, category 4a: 2002, 2004, 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Dissolved Oxygen, category 5: 2012, 2014, 2016, 2018, and 2020 Emma Creek near Sedgwick (SC534) Total phosphorus, category 5: 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Biology, category 4a: 2002, 2004, 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Dissolved Oxygen, category 5: 2004, 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Little Arkansas River at Valley Center (SC282) Total phosphorus, category 5: 2008, 2010, 2012, 2014, 2016, 2018, and 2020 Biology, category 4a: 2002, 2004, 2008, 2010, 2012, 2014, 2016, 2018, and 2020

Water Quality Criteria Narrative Nutrient Criteria 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 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)).

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)).

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)).

Numeric Dissolved Oxygen Criteria 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 5.0 mg/L (K.A.R. 28-16-28e(e), Table 1g).

Numeric pH Criteria 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 2020 303(d) Phosphorus levels in the Little Arkansas River are consistently high. Excessive nutrients are not being controlled and are thus impairing aquatic life, contact recreation, and domestic water supply. 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) Stations – Kansas Department of Health and Environment SC246: Active permanent station for Little Arkansas River at Alta Mills, located at latitude 38.112, longitude -97.592. Period of record: March 21, 1990 to December 10, 2019.

SC705: Active rotational station for Black Kettle Creek near Halstead, located at latitude 38.029, longitude -97.521. Period of record: May 3, 1995 to November 28, 2018. SC703: Active rotational station for Kisiwa Creek near Halstead, located at latitude 37.957, longitude -97.501. Period of record: July 13, 1994 to November 28, 2018. SC534: Active rotational station for Emma Creek near Sedgwick, located at latitude 37.956, longitude -97.442. Period of record: March 21, 1990 to November 28, 2018. SC282: Active permanent station for Little Arkansas River at Valley Center, located at latitude 37.832, longitude -97.388. Period of record: March 21, 1990 to December 10, 2019.

Stream Probabilistic (SP) Stations – Kansas Department of Health and Environment SPB190: Horse Creek. Period of record: 2012. SPB486: West Emma Creek. Period of record: 2015 and 2017. SPB662: Middle Emma Creek. Period of record: 2017. SPA475: Little Arkansas River. Period of record: 2009.

Water Quality Stations – U.S. Geological Survey 07143665: Little Arkansas River at Alta Mills. Period of record: 2006 to 2008. 07143672: Little Arkansas River near Halstead. Period of record: 1995 to 2019. 07143965: West Emma Creek. Period of record: 2007 to 2008. 07144000: East Emma Creek. Period of record: 2007 to 2008. 07144035: Emma Creek near Sedgwick. Period of record: 2007. 375721097263300: Emma Creek at 72nd Street. Period of record: 2007 to 2008. 375350097262800: Little Arkansas River upstream of ASR Facility. Period of record: 2011 to 2019. 375348097262800: Discharge from the Little Arkansas River ASR Facility. Period of record: 2012 to 2016. 375344097261600: Little Arkansas River downstream of ASR Facility. Period of record: 2011. 07144100: Little Arkansas near Sedgwick. Period of record: 1995 to 2019. 07144200: Little Arkansas River at Valley Center. Period of record: 2006 to 2008.

Stream Biology (SB) Station – Kansas Department of Health and Environment SB727: Active permanent station for Little Arkansas River, located at latitude 38.029, longitude -97.541. Period of record: 2013 to 2018.

Streamflow Gages – U.S. Geological Survey 07143665: Little Arkansas River at Alta Mills. Period of record: January 1, 1990 to December 31, 2019. Located at Little Arkansas River at Alta Mills (SC246). 07144100: Little Arkansas River near Sedgwick. Period of record: October 1, 1993 to December 31, 2019. 07144200: Little Arkansas River at Valley Center. Period of record: January 1, 1990 to December 31, 2019. Located at Little Arkansas River at Valley Center (SC282).

Hydrology Streamflows for this TMDL were analyzed using U.S. Geological Survey (USGS) streamgage data from Little Arkansas River at Alta Mills (07143665), Little Arkansas River near Sedgwick (07144100), and Little Arkansas River at Valley Center (07144200). The gages Little Arkansas

River at Alta Mills (07143665) and Valley Center (07144200) have streamflow data available for the period of record January 1, 1990 to December 31, 2019. The Little Arkansas River near Sedgwick (07144100) gage has streamflow data available for the period of record October 1, 1993 to December 31, 2019.

Streamflow for the Kansas Department of Health and Environment (KDHE) stream chemistry (SC) station Little Arkansas River at Alta Mills (SC246) is based upon streamflow measurements at the colocated USGS Little Arkansas River at Alta Mills (07143665) streamgage (Table 3). Streamflow for the Black Kettle Creek near Halstead (SC705) is calculated using a watershed area ratio based upon the USGS Little Arkansas River near Sedgwick (07144100) streamgage and its drainage area. Flow conditions for the Kisiwa Creek near Halstead (SC703) were calculated using a watershed area ratio based upon the USGS Little Arkansas River at Valley Center (07144200) streamgage and its drainage area. Flow conditions for the Emma Creek near Sedgwick (SC534) were calculated using a regression based upon the USGS Little Arkansas River at Valley Center (07144200) streamgage and estimated long-term flows for Emma Creek (Table 4; Perry et al., 2004). Flow conditions for the Little Arkansas River at Valley Center (SC282) are based upon streamflow measurements at the colocated USGS Little Arkansas River at Valley Center (07144200) streamgage.

Table 3. Flow conditions and drainage area at U.S. Geological Survey gages and Kansas Department of Health and Environment stream chemistry (SC) stations for the Little Arkansas River from Alta Mills to Valley Center. Drainage Mean Percent Flow Exceedance (cfs) Station Area (mi2) Flow (cfs) 90% 75% 50% 25% 10% Little Arkansas River at Alta Mills (07143665) 681 201 3.20 7.60 16.7 50.0 261

Little Arkansas River at Alta Mills (SC246) 539 159 2.53 6.02 13.2 39.6 207

Black Kettle Cr (SC705) 39.6 11.5 0.54 1.05 1.90 4.25 18.0

Kisiwa Cr (SC703) 116 32.0 1.58 3.28 6.14 14.0 59.8

Little Arkansas River near Sedgwick (07144100) 1,165 370 16.0 30.8 55.8 125 530

Emma Cr (SC534) 174 29.0 2.05 3.47 5.86 12.4 50.8

Little Arkansas River at Valley Center (07144200) 1,250 364 17.0 35.2 66.0 150 643

Little Arkansas River at Valley Center (SC282) 171 49.8 2.33 4.82 9.03 20.5 88.0

Table 4. Long-term estimated flows from the U.S. Geological Survey (USGS) for the Little Arkansas River and its tributaries from Alta Mills to Valley Center (Perry et al., 2004). KSWR Drainage Mean 2-year USGS Percent Flow Exceedance (cfs) Stream CUSEGA County Area Flow Peak Site Number (mi2) (cfs) 90% 75% 50% 25% 10% (cfs) Little Arkansas R 2969 1103001214 RC 42.1 6.04 0 0 0.48 1.40 4.76 926 Horse Cr 2968 1103001219 RC 46.7 6.54 0 0 0.68 1.77 5.46 942 Little Arkansas R 3102 1103001214 RC 101 9.46 0 0.20 0.80 1.90 6.90 1,200 Salt Cr 3101 1103001221 RC 21.6 3.87 0 0 0 0.31 2.44 938 Dry Cr 3122 1103001222 RC 15.7 2.69 0 0 0 0 1.16 780 Little Arkansas R 3199 1103001214 MP, RC 151 25.1 0 0 0.65 3.87 26.3 1,640 Lone Tree Cr 3196 1103001220 MP 69.4 15.1 0 0.02 1.47 4.80 15.8 1,610 Sand Cr 3249 1103001223 MP, RC 47.3 10.4 2.58 3.83 4.90 7.27 13.5 958 Little Arkansas R 3473 1103001214 HV, RN 441 127 4.46 9.52 19.4 43.4 182 3,060 Black Kettle Cr 3632 11030012368 HV 76.4 17.4 0 0.34 1.80 5.53 17.5 1,400 Little Arkansas R 3729 1103001210 HV 840 239 6.90 11.9 25.7 68.2 341 5,180 Kisiwa Cr 3750 1103001215 HV 119 31.7 2.75 4.93 9.17 18.6 42.6 1,480 Little Arkansas R 3777 110300129 HV 963 255 11.1 18.3 35.8 83.8 375 5,390 Emma Cr, West 3660 110300128 HV 94.2 23.3 0.06 0.90 2.94 8.41 25.2 1,950 Emma Cr, Middle 3659 110300127 HV 73.5 18.0 0 0.20 1.66 5.43 17.8 3,400 Emma Cr 3776 110300126 HV 175 43.1 0.71 2.03 5.58 16.2 50.0 4,330 Little Arkansas R 3799 110300125 HV 1,140 277 15.5 24.1 44.1 98.2 414 5,860 Little Arkansas R 3907 110300123 HV, SG 1,260 296 18.7 29.0 52.3 113 453 6,170 Jester Cr, W Fk 3717 1103001218 HV 14.3 3.88 0 0 0.01 0.34 2.49 1,010 Jester Cr, E Fk 3718 110300129002 HV 12.9 3.74 0 0 0.01 0.33 2.45 972 Gooseberry Cr 3828 1103001217 SG 11.4 4.16 0 0 0.36 1.03 3.66 918 Jester Cr 3906 110300122 SG 63.7 22.0 0 1.34 4.12 10.7 27.8 1,960 Little Arkansas R 4072 110300121 SG 1,350 312 21.0 33.0 60.0 127 488 6,290

Of the KDHE SC stations in the Little Arkansas River Watershed, the Little Arkansas River at Alta Mills (SC246) is closest to the headwaters of the river. Its largest tributary, with an estimated long-term mean flow of 15.1 cubic feet per second (cfs), is Lone Tree Creek. Downstream in the watershed, the main stem station Little Arkansas River at Valley Center (SC282) has several larger tributaries, including Kisiwa Creek (mean flow of 31.7 cfs) and Emma Creek (mean flow of 43.1 cfs). Aggregated, increasing flow accumulations further downstream in the watershed are reflected in the flow duration curves for the three USGS streamgages used to calculate flow for the KDHE SC stations (Figure 2). Throughout most flow conditions, flows at Little Arkansas River at Valley Center (07144200) are at least twice those at

Little Arkansas River at Alta Mills (07143665). During lower flow conditions (50 to 100% flow exceedance), streamflows can be as much as five times higher at Little Arkansas River at Valley Center (07144200).

Figure 2. Flow duration curve for U. S. Geological Survey streamgages Little Arkansas River at Alta Mills (07143665), Little Arkansas River near Sedgwick (07144100), and Little Arkansas River at Valley Center (07144200).

Much of this watershed overlies aquifers, including the High Plains, Dakota, and an alluvial aquifer (Figure 3). The largest aquifer in this watershed is the High Plains which underlies the alluvial aquifer, as well. Interactions between surface water and groundwater in these aquifers can have a significant impact on hydrology, particularly when influenced by anthropogenic alterations. One example of this is a portion of the High Plains Aquifer known as the Equus Beds. This aquifer has been susceptible to over-pumping, resulting in decreased aquifer levels (Stone et al., 2019). The impacts of reduced groundwater tables are particularly noticeable during low flow conditions when streams overlying the Equus Beds have little to no streamflow (Perry et al., 2004). As the Equus Beds Aquifer is a primary water source for the City of Wichita, the city is implementing a project to restore storage capacity and recover the aquifer (U.S. Geological Survey, 2019). The aquifer storage and recovery (ASR) Facility withdraws surface water from the Little Arkansas River during high flow conditions, treats it to drinking water guidelines, and injects it into the Equus Beds through wells and basins. The ASR Facility consists of two phases: Phase I became operable in 2007; Phase II became operable in 2013. As the aquifer, ASR Facility, and their management impact hydrology in the watershed, their influence is important to consider while discussing streamflow and potential impacts to water quality.

Figure 3. Map of aquifers for Little Arkansas River Watershed.

The highest mean annual streamflows occurred in 1993 and 2019 for the Little Arkansas River at Alta Mills (07143665), 1995 and 2019 for the Little Arkansas River near Sedgwick (07144100), and 1993 and 1995 for the Little Arkansas River at Valley Center (07144200; Figures 4 to 6). The highest median annual streamflows occurred in 1993 and 1998 for the Little Arkansas River at Alta Mills (07143665), 1998 and 1999 for the Little Arkansas River near Sedgwick (07144100), and 1993 and 1998 for the Little Arkansas River at Valley Center (07144200). Annual mean streamflows were lowest in 2006 and annual median streamflows were lowest in 2012 for all stations. Overall, annual mean and median streamflows at these stations are below the 30-year mean and median a majority of the time, with the upstream Little Arkansas River at Alta Mills (07143665) streamflow below its 30-year mean up to 63% of the time.

Figure 4. Annual mean and median flows for U. S. Geological Survey streamgage Little Arkansas River at Alta Mills (07143665).

Figure 5. Annual mean and median flows for U. S. Geological Survey streamgage Little Arkansas River near Sedgwick (07144100).

Figure 6. Annual mean and median flows for U. S. Geological Survey streamgage Little Arkansas River at Valley Center (07144200).

Peak annual flows varied among the USGS streamgages for the period of records available (Figure 7). The highest peak annual streamflows occurred in 1998 for Little Arkansas River at Alta Mills (07143665) and near Sedgwick (07144100) and 1993 for Little Arkansas River at Valley Center (07144200). Annual peak flow years correspond to annual median high flows across all stations. Throughout the watershed, streamgage trends in annual flows generally coincide with National Oceanic and Atmospheric Administration (NOAA) total annual precipitation from Inman, Kansas (USC00143974), as well. Trends are more variable for years with higher flows but correspond well to years with lower flows. For example, some of the lowest peak annual streamflows occurred in 2006 and 2012, which correspond to low annual means and medians in 2006 and 2012 for all stations; these years also coincide with some of the lowest annual accumulated precipitation.

Seasonally, high flows occur in spring (April through June) for the Little Arkansas River at Alta Mills (07143665), Little Arkansas River near Sedgwick (07144100), and Little Arkansas River at Valley Center (07144200), Figures 8 to 10). Spring streamflows are skewed by high flow events, likely due to increased precipitation and runoff. For all stations, summer-fall (July through October) and winter (November through March) streamflows are comparatively lower. Amongst each station, summer-fall and winter flows have smaller ranges and medians that are similar to each other; however, summer-fall mean streamflows are consistently higher than winter means.

Figure 7. Annual peak flows for U. S. Geological Survey streamgages and annual total precipitation at National Oceanic and Atmospheric Association station at Inman (USC00143974).

Figure 8. Flow by season for U. S. Geological Survey streamgage Little Arkansas River at Alta Mills (07143665).

Figure 9. Flow by season for U. S. Geological Survey streamgage Little Arkansas River near Sedgwick (07144100).

Figure 10. Flow by season for U. S. Geological Survey streamgage Little Arkansas River at Valley Center (07144200).

Total Phosphorus Concentrations Overall, total phosphorus (TP) concentrations for the Little Arkansas River Watershed increase minimally between the main stem stations (Figure 11). The upstream Little Arkansas River at Alta Mills (SC246) has a mean of 0.607 milligrams per liter (mg/L) and a median of 0.525 mg/L while the downstream Little Arkansas River at Valley Center (SC282) has a mean of 0.626 mg/L and a median of 0.561 mg/L (Table 5).

Figure 11. Total phosphorus by station from 1990 to 2019 for the Little Arkansas River Watershed.

Table 5. Total phosphorus concentration summary statistics by station from for the Little Arkansas River Watershed. Mean Median Maximum Minimum Sample Station (mg/L) (mg/L) (mg/L) (mg/L) Number Little Arkansas River at Alta Mills (SC246) 0.607 0.525 2.15 0.140 151 Black Kettle Creek near Halstead (SC705) 0.846 0.741 1.60 0.280 16 Kisiwa Creek near Halstead (SC703) 1.06 0.880 2.00 0.527 9 Emma Creek near Sedgwick (SC534) 0.757 0.700 2.01 0.110 38 Little Arkansas River at Valley Center (SC282) 0.626 0.561 1.97 0.150 152

Total phosphorus concentrations increase substantially among the tributary stations Black Kettle Creek near Halstead (SC705), Kisiwa Creek near Halstead (SC703), and Emma Creek near Sedgwick (SC534). Samples for the tributary stations are collected on a rotational basis, resulting in reduced resolution for analysis compared to the main stem stations. Because of this, outliers can have disproportionate effects at tributary stations; for this reason, a sample collected at Kisiwa Creek near Halstead (SC703) with a TP concentration of 10.2 mg/L has been excluded

from the following analyses. Despite this, Kisiwa Creek near Halstead (SC703) retains the highest TP mean and median in the watershed, with concentrations of 1.06 and 0.880 mg/L, respectively. Although tributaries are contributing higher TP concentrations than main stem stations, they are likely moderated by the increase in flow at the main stem station Little Arkansas River at Valley Center (SC282).

Most daily TP samples collected for the main stem stations are below 1.00 mg/L TP (Figures 12 and 13). However, samples at these stations have reached concentrations as high as 2.15 mg/L. The trend in TP concentrations at both stations is decreasing over time, with a more defined trend at Little Arkansas River at Valley Center (SC282). The highest annual mean and median TP concentrations occurred from 1990 to 1992, approaching or exceeding 1.00 mg/L TP (Table 6). These years were characterized by a period of lower flows in the watershed. The only similar concentration outside of this time frame occurred at Little Arkansas River at Alta Mills (SC246) in 2007, with a mean TP concentration of 0.934 mg/L.

Figure 12. Total phosphorus single day samples by date and annual mean and median for the Little Arkansas River at Alta Mills (SC246).

The lowest mean annual TP concentrations occurred in 1997 and 2019 for Little Arkansas River at Alta Mills (SC246), with concentrations of 0.405 and 0.410 mg/L, respectively; and in 2000, 2011, and 2019 for Little Arkansas River at Valley Center (SC282), with concentrations of 0.392, 0.394, and 0.330 mg/L, respectively. The lowest median TP concentrations occurred in 1998 and 2004 for Little Arkansas River at Alta Mills (SC246), with concentrations of 0.340 and 0.354 mg/L, respectively; and in 2000, 2004, and 2019 for Little Arkansas River at Valley Center (SC282), with concentrations of 0.385, 0.373, and 0.320 mg/L, respectively. It should be noted that 2019 was characterized by extremely high flows, resulting in flooding throughout

much of the state. Low TP concentrations from this year may be due to these high flows rather than an improvement in water quality.

When comparing mean TP concentrations from 1990 to 1999 with concentrations from 2000 to 2019, mean concentrations have decreased for both main stem stations by up to 32% (Table 6). Median TP concentrations, however, vary marginally between the stations’ periods of record. The median for Little Arkansas River at Alta Mills (SC246) has increased by 4% while the median for Little Arkansas River at Valley Center (SC282) has decreased by 6%.

Figure 13. Total phosphorus single day samples by date and annual mean and median for the Little Arkansas River at Valley Center (SC282).

The tributary stations Black Kettle Creek near Halstead (SC705), Kisiwa Creek near Halstead (SC703), and Emma Creek near Sedgwick (SC534) demonstrate a wide TP concentration range from 0.110 to 2.01 mg/L (Figure 14). The highest TP concentrations occurred in 2014 for the Black Kettle Creek near Halstead (SC705), with a concentration of 1.60 mg/L, and for the Kisiwa Creek near Halstead (SC703), with a concentration of 2.00 mg/L. For Emma Creek near Sedgwick (SC534), the highest annual mean TP concentration of 1.28 mg/L occurred in 1990, and the highest annual median TP concentration of 1.10 mg/L occurred in 2006 (Table 7). These high annual TP concentrations coincide with lower mean and median flows in the watershed. The lowest annual mean and median TP concentrations occurred in 2018 for the Black Kettle Creek near Halstead (SC705), with a mean and median of 0.605 mg/L, and for the Emma Creek near Sedgwick (SC534), with a mean of 0.563 mg/L and a median of 0.470 mg/L. For the Kisiwa Creek near Halstead (SC703), the lowest annual mean and median TP concentrations occurred in 1998 with a mean of 0.672 mg/L and a median of 0.640 mg/L.

Table 6. Total phosphorus concentration annual summary statistics for main stem stations for the Little Arkansas River Watershed. Total Phosphorus (mg/L) for Total Phosphorus (mg/L) for Little Year Little Arkansas River at Alta Mills (SC246) Arkansas River at Valley Center (SC282) Mean Median Sample Number Mean Median Sample Number 1990 1.01 0.980 5 0.916 0.960 5 1991 1.11 1.13 6 1.27 1.18 6 1992 0.812 0.790 6 1.17 1.21 6 1993 0.433 0.440 6 0.505 0.460 6 1994 0.547 0.460 6 0.570 0.610 6 1995 0.546 0.522 6 0.625 0.603 6 1996 0.637 0.551 6 0.639 0.577 6 1997 0.405 0.437 6 0.477 0.495 6 1998 0.546 0.340 5 0.619 0.558 6 1999 0.430 0.400 6 0.480 0.500 6 2000 0.420 0.380 5 0.392 0.385 4 2001 0.611 0.530 6 0.609 0.520 6 2002 0.536 0.480 6 0.644 0.623 6 2003 0.717 0.471 6 0.765 0.679 6 2004 0.451 0.354 6 0.471 0.373 6 2005 0.638 0.650 5 0.576 0.570 5 2006 0.566 0.556 6 0.661 0.617 6 2007 0.934 0.610 6 0.668 0.647 6 2008 0.580 0.584 5 0.686 0.637 5 2009 0.451 0.469 4 0.478 0.449 4 2010 0.624 0.662 4 0.627 0.583 4 2011 0.470 0.470 2 0.394 0.459 3 2012 0.784 0.474 4 0.450 0.451 4 2013 0.691 0.717 4 0.606 0.584 4 2014 0.533 0.530 4 0.630 0.660 4 2015 0.547 0.595 4 0.530 0.545 4 2016 0.440 0.435 4 0.433 0.415 4 2017 0.552 0.605 4 0.583 0.595 4 2018 0.550 0.495 4 0.453 0.445 4 2019 0.410 0.430 4 0.330 0.320 4 1990-1999 0.648 0.491 58 0.727 0.590 59 2000-2019 0.575 0.513 93 0.549 0.558 93 Definition: Bold - summary data.

When comparing mean and median TP concentrations from 1990 to 1999 with concentrations from 2000 to 2019, concentrations have increased for Black Kettle Creek (SC705) and Kisiwa Creek (SC703) near Halstead by over 50% (Table 7). During the same time periods, the mean and median TP concentrations for the Emma Creek near Sedgwick (SC534) have decreased by over 30%.

Figure 14. Total phosphorus single day samples by date for the tributaries to the Little Arkansas River Watershed.

Table 7. Total phosphorus concentration annual summary statistics for tributary stations for the Little Arkansas River Watershed. Total Phosphorus (mg/L) for Total Phosphorus (mg/L) Total Phosphorus (mg/L) Black Kettle Creek near for Kisiwa Creek near for Emma Creek near Year Halstead (SC705) Halstead (SC703) Sedgwick (SC534) Sample Sample Sample Mean Median Mean Median Mean Median Number Number Number 1990 – – – – – – 1.28 0.910 5 1994 – – – – – – 0.687 0.750 6 1995 0.660 0.680 3 – – – – – – 1998 – – – 0.672 0.640 4 0.580 0.520 6 1999 0.686 0.690 5 – – – – – – 2002 – – – 1.06 1.06 1 0.637 0.553 6 2003 1.02 0.960 3 – – – – – – 2006 – – – – – – 0.960 1.10 3 2010 1.13 1.13 2 1.73 1.73 1 0.631 0.574 4 2014 1.60 1.60 1 2.00 2.00 1 0.823 0.900 4 2018 0.605 0.605 2 1.05 1.05 2 0.563 0.470 4 1990-1999 0.673 0.685 8 0.672 0.640 4 0.848 0.750 17 2000-2019 1.09 1.04 8 1.46 1.39 5 0.723 0.574 21 Definition: – - No data; Bold - summary data.

In addition to routinely sampled SC stations, the Little Arkansas River Watershed also contains four stream probabilistic (SP) stations (Table 8). Stream probabilistic stations are randomly selected locations throughout the state which are sampled four times per year. Available data is presented as a mean because of the nature of sampling at these stations. Data from Horse Creek (SPB190) and West Emma Creek (SPB486) suggests that concentrations in tributaries unaffected by point sources can have TP concentrations less than 0.101 mg/L (Figure 15). Samples collected further downstream in more impacted portions of the Little Arkansas River Watershed are from Middle Emma Creek (SPB662) and Little Arkansas River (SPA475).

Table 8. Total phosphorus (TP) concentration means and number of samples (N) by stream probabilistic (SP) station from 2009 to 2017 for the Little Arkansas River Watershed. Sample Mean TP Stream Chemistry Station SP Station SP Stream N Year (mg/L) Little Arkansas River at Alta Mills (SC246) SPB190 Horse Cr 2012 0.101 1 SPB486 West Emma Cr 2015, 2017 0.442 8 Emma Creek near Sedgwick (SC534) SPB662 Middle Emma Cr 2017 0.515 4 Little Arkansas River at Valley Center (SC282) SPA475 Little Arkansas R 2009 0.561 4

Figure 15. Total phosphorus for stream probabilistic stations for the Little Arkansas River Watershed.

Besides KDHE-collected data, this watershed also contains 11 USGS water quality stations (Table 9). As with the SP stations, the USGS water quality stations are located in the watersheds for Little Arkansas River at Alta Mills (SC246), Emma Creek near Sedgwick (SC534), and Little Arkansas River at Valley Center (SC282). Most data collected from these stations span a time

period from one to four years (Figure 16). However, there are two consistently sampled stations on the Little Arkansas River at Halstead and Sedgwick (Figure 17).

The USGS station co-located with the KDHE station Little Arkansas River at Alta Mills (SC246) has a median TP concentration of 0.655 mg/L, which is higher than the median from the SC station (0.525 mg/L). Samples collected within the Emma Creek near Sedgwick (SC534) Watershed indicate that East (Middle) Emma Creek has the highest median TP concentration among the Emma Creek segments (1.01 mg/L). Several stations within the Little Arkansas River at Valley Center (SC282) Watershed relate to the operations of the previously mentioned ASR Facility. Samples of the ASR Facility discharge indicate that the median TP concentration discharged from this facility (2.67 mg/L) is more than three times the median upstream concentration (0.800 mg/L). Meanwhile, the USGS station co-located with KDHE station Little Arkansas River at Valley Center (SC282) has a median TP concentration of 0.700 mg/L, which is higher than the median from the SC station (0.561 mg/L).

The two main USGS water quality stations on the Little Arkansas River are within the Little Arkansas River at Valley Center (SC282) Watershed. The stations, located at Halstead and Sedgwick, have data collected on a routine basis from 1995 to 2019. The median at Halstead (0.580 mg/L) is similar to those at main stem KDHE stations. The median at Sedgwick (0.670 mg/L) is higher than concentrations at main stem KDHE stations.

Table 9. Total phosphorus (TP) concentration means and number of samples (N) by U.S Geological Survey water quality stations from 1995 to 2019 for the Little Arkansas River Watershed. Stream Chemistry USGS Water Sample Median USGS Water Quality Station N Station Quality Station Year TP (mg/L) Little Arkansas River 07143665 Little Arkansas R at Alta Mills 2006-2008 0.655 4 at Alta Mills (SC246) 07143965 West Emma Cr 2007-2008 0.590 5 Emma Creek near 07144000 East Emma Cr 2007-2008 1.01 5 Sedgwick (SC534) 07144035 Emma Cr 2007 0.790 1 375721097263300 Emma Cr at 72nd St. 2007-2008 0.785 4 07143672 Little Arkansas R near Halstead 1995-2019 0.580 183 375350097262800 Little Arkansas R Upstream of ASR 2011-2019 0.800 50 Little Arkansas 375348097262800 Discharge from Little Arkansas R ASR 2012-2016 2.67 26 River at Valley Center (SC282) 375344097261600 Little Arkansas R Downstream of ASR 2011 0.850 1 07144100 Little Arkansas R near Sedgwick 1995-2019 0.670 316 07144200 Little Arkansas R at Valley Center 2006-2008 0.700 5

Figure 16. Total phosphorus for U.S. Geological Survey minor water quality stations for the Little Arkansas River Watershed and the ASR facility.

Figure 17. Total phosphorus for U.S. Geological Survey major water quality stations for the Little Arkansas River Watershed.

Main stem individual TP samples collected on concurrent days exhibit a clearly defined 1:1 relationship when comparing samples from upstream Little Arkansas River at Alta Mills (SC246) and downstream Little Arkansas River at Valley Center (SC282; Figure 18). The majority of samples collected below 1.5 mg/L adhere to this relationship; however, TP concentrations become more variable as concentrations increase, possibly due to the influence of runoff events.

Figure 18. Total phosphorus at downstream Little Arkansas River at Valley Center (SC282) versus upstream Little Arkansas River at Alta Mills (SC246) for concurrent day samples, March 21, 1990 to December 10, 2019.

Total phosphorus concentrations for the main stem stations Little Arkansas River at Alta Mills (SC246) and Valley Center (SC282) and the tributary station Emma Creek near Sedgwick (SC534) are highest during high (0 to 25%) and low (76 to 100%) flow conditions (Figure 19). For example, the Little Arkansas River at Valley Center (SC282) has mean and median TP concentrations of 0.744 and 0.715 mg/L, respectively, during high flow conditions and mean and median TP concentrations of 0.732 and 0.616 mg/L, respectively, during low flow conditions (Table 10). Meanwhile, concentrations for normal (26 to 75%) flow conditions are up to one- third less, when concentrations decline to a mean of 0.514 mg/L and median of 0.480 mg/L. This pattern indicates high TP concentrations at stations like Little Arkansas River at Valley Center (SC282) are impacted by runoff under high flow conditions and point source discharges under low flow conditions.

The remaining tributaries of Black Kettle Creek (SC705) and Kisiwa Creek (SC703) near Halstead also exhibit comparably high TP concentrations during high flow conditions. Total phosphorus concentrations at low flow conditions are not available at these stations due to the

rotational nature of their sampling and the propensity for these tributaries to have little or no flow. Similar to the other stations, Black Kettle Creek near Halstead (SC705) displays a decline in TP concentrations under normal flow conditions. Kisiwa Creek near Halstead (SC703), however, has an increase in TP mean and median concentrations at normal flow conditions that are nearly twice the concentrations at high flow conditions.

Figure 19. Total phosphorus by percent flow exceedance and station for the Little Arkansas River Watershed.

Seasonally, spring has greater mean and median TP concentrations than summer-fall or winter for the main stem stations Little Arkansas River at Alta Mills (SC246) and Valley Center (SC282) and the tributary station Emma Creek near Sedgwick (SC534; Table 10; Figure 20). This indicates that nonpoint source contributions during spring runoff conditions may be a strong factor for TP loading in these watersheds; however, it should be noted that concentrations throughout the seasons remain similar for both main stem stations. Black Kettle Creek (SC705) and Kisiwa Creek (SC703) near Halstead have more variable concentration patterns. Black Kettle Creek near Halstead (SC705) has its highest mean and median TP concentrations in the summer-fall; concentrations in the spring and winter are similar at this station. Kisiwa Creek near Halstead (SC703) has its highest mean and lowest median in the summer-fall while mean and median concentrations remain consistently high in the spring.

Table 10. Total phosphorus concentration summary statistics by season (spring: April through June, summer-fall: July through October, winter: November through March), flow range, and station for the Little Arkansas River Watershed.

Flow Spring Summer-fall Winter All Exceedance (%) Mean Median N Mean Median N Mean Median N Mean Median N Total Phosphorus (mg/L) for Little Arkansas River at Alta Mills (SC246) 0-25 0.693 0.650 17 0.883 0.645 10 0.658 0.630 9 0.737 0.640 36 26-75 0.621 0.510 15 0.516 0.500 27 0.398 0.346 38 0.480 0.428 80 76-100 0.858 0.787 7 0.542 0.520 12 0.891 0.717 16 0.765 0.610 35 0-100 0.695 0.639 39 0.597 0.530 49 0.560 0.500 63 0.607 0.525 151 Total Phosphorus (mg/L) for Black Kettle Creek near Halstead (SC705) 0-25 0.928 0.820 4 0.798 0.781 5 1.20 1.20 2 0.918 0.789 11 26-75 0.280 0.280 1 1.60 1.60 1 0.517 0.540 3 0.686 0.540 5 76-100 – – – – – – – – – – – – 0-100 0.799 0.680 5 0.932 0.785 6 0.790 0.701 5 0.846 0.741 16 Total Phosphorus (mg/L) for Kisiwa Creek near Halstead (SC703) 0-25 1.13 1.06 3 0.745 0.745 2 0.704 0.704 2 0.896 0.800 7 26-75 – – – 2.00 2.00 1 1.30 1.30 1 1.65 1.65 2 76-100 – – – – – – – – – – – – 0-100 1.13 1.06 3 1.16 0.800 3 0.902 0.880 3 1.06 0.880 9 Total Phosphorus (mg/L) for Emma Creek near Sedgwick (SC534) 0-25 1.05 0.826 4 0.810 0.810 2 0.491 0.491 2 0.849 0.672 8 26-75 0.993 0.960 3 0.791 0.840 7 0.526 0.400 11 0.681 0.580 21 76-100 1.21 1.20 3 0.814 0.883 3 0.527 0.720 3 0.852 0.883 9 0-100 1.08 1.04 10 0.800 0.855 12 0.522 0.437 16 0.757 0.700 38 Total Phosphorus (mg/L) for Little Arkansas River at Valley Center (SC282) 0-25 0.714 0.730 19 0.746 0.703 12 0.809 0.729 8 0.744 0.715 39 26-75 0.625 0.525 14 0.619 0.570 22 0.418 0.430 40 0.514 0.480 76 76-100 0.968 0.794 6 0.567 0.600 15 0.798 0.613 16 0.732 0.616 37 0-100 0.721 0.640 39 0.634 0.630 49 0.562 0.477 64 0.626 0.561 152 Definition: – - No data

Figure 20. Total phosphorus by season and station for the Little Arkansas River Watershed.

The variable influence of point and nonpoint sources for the Little Arkansas River Watershed are also evident in individual stream samples (Figures 21 and 22). This influence is most pronounced for the Little Arkansas River at Alta Mills (SC246). During higher flow conditions, high TP concentrations are more likely in the spring and summer-fall and are likely the result of runoff due to precipitation. During lower flow conditions, high TP concentrations are predominantly collected in the winter and are likely due to point source influence; this is true for the Little Arkansas River at Valley Center (SC282), as well. Due to the rotational nature of their sampling and the lack of samples during some seasons and flow conditions, tributary stations in the watershed have a sparse seasonal dataset with indistinct patterns.

Figure 21. Total phosphorus by percent flow exceedance and season for the Little Arkansas River at Alta Mills (SC246).

Figure 22. Total phosphorus by percent flow exceedance and season for the Little Arkansas River at Valley Center (SC282).

To further assess TP load sources for the Little Arkansas River Watershed, a mass balance was estimated based upon median TP concentrations and streamflow for each watershed (Perry, 2004; Table 11). The total load is accumulative and reflects the total TP load at each station. The TP load by watershed is incremental and reflects the TP load contributed within each watershed. While not addressed by this TMDL, the watersheds for both Turkey Creek near Alta Mills (SC533) and Sand Creek near Sedgwick (SC535) have approved TP TMDLs. They are considered here as tributaries for mass balance purposes. Turkey Creek near Alta Mills (SC533) is a tributary to Little Arkansas River at Alta Mills (SC246) and Sand Creek near Sedgwick (SC535) is a tributary to Little Arkansas River at Valley Center (SC282). The mass balance calculation suggests that 23% of the load reaching the Little Arkansas River at Valley Center (SC282) originates from Turkey Creek near Alta Mills (SC533) and Sand Creek near Sedgwick (SC535). Of the remaining 77% of TP load, the majority is contributed by the watersheds for Kisiwa Creek near Halstead (SC703; 24%) and Little Arkansas River at Alta Mills (SC246; 23%).

Table 11. Estimated mass balance for total phosphorus (TP) loads based upon median streamflow (Perry et al., 2004) for the Little Arkansas River Watershed. Median TP Load Percent of Median Total TP (50%) by Total Load by Station TP Load Stream- Watershed Watershed (mg/L) (lbs/day) flow (cfs) (lbs/day) (%) Turkey Creek near Alta Mills (SC533) 2.89 0.673 10.5 10.5 6 Little Arkansas River at Alta Mills (SC246) 19.4 0.525 55.0 44.5 23 Black Kettle Creek near Halstead (SC705) 1.80 0.741 7.20 7.20 4 Kisiwa Creek near Halstead (SC703) 9.17 0.880 43.6 43.6 24 Emma Creek near Sedgwick (SC534) 5.58 0.700 21.1 21.1 12 Sand Creek near Sedgwick (SC535) 3.22 1.74 30.3 30.3 17 Little Arkansas River at Valley Center (SC282) 60.0 0.561 182 24.6 14 Total 60.0 0.561 182 182 100

Total Phosphorus and Other Water Quality Parameters Total phosphorus has well-established and defined relationships with orthophosphate (OP) and total suspended solids (TSS). These relationships are examined further in order to delineate potential sources of TP loading to the Little Arkansas River Watershed.

Orthophosphate The soluble portion of TP that is readily available for biological use is OP. It is commonly found in higher concentrations in effluent, such as the discharge of municipal wastewater treatment plants (WWTPs) or in runoff from livestock sources. Only samples measuring above the reporting limit are included in the analysis presented resulting in a left censored data set which may overestimate true OP concentration means (Table 12). In addition, reporting limits for OP have changed throughout the period of record: 0.01 mg/L from 1995 to 1996, 0.02 mg/L from 1997 to February 2002, and 0.25 mg/L from March 2002 to 2019. All the stations in the watershed have 63% or greater detection of OP. The highest censored mean detections are all from the tributary watersheds: 0.54 mg/L at Black Kettle Creek near Halstead (SC705), 0.94

mg/L at Kisiwa Creek near Halstead (SC703), and 0.63 mg/L at Emma Creek near Sedgwick (SC534).

Table 12. Mean of detected orthophosphate (OP) samples, mean ratio of OP and total phosphorous (TP), sample number, and percentage of samples greater than the analytical reporting limit (> RL) separated by reporting limit increases for the Little Arkansas River Watershed, February 8, 1995 to September 17, 2019. Orthophosphate Period of Record Station Sample Information 1995-1996 1997-Feb. 2002 Mar. 2002-2019 1995-2019 (0.01 mg/L) (0.02 mg/L) (0.25 mg/L) Mean (mg/L) 0.25 0.20 0.43 0.36 Little Arkansas River at Sample Number 12 10 44 67 Alta Mills (SC246) Samples > RL (%) 100 63 56 63 Mean Ratio OP:TP 0.47 0.36 0.63 0.56 Mean (mg/L) 0.24 – 0.69 0.54 Black Kettle Creek near Sample Number 3 – 6 9 Halstead (SC705) Samples > RL (%) 100 – 75 82 Mean Ratio OP:TP 0.36 – 0.65 0.55 Mean (mg/L) – – 0.94 0.94 Kisiwa Creek near Sample Number – – 5 5 Halstead (SC703) Samples > RL (%) – – 100 100 Mean Ratio OP:TP – – 0.69 0.69 Mean (mg/L) – – 0.63 0.63 Emma Creek near Sample Number – – 16 16 Sedgwick (SC534) Samples > RL (%) – – 80 80 Mean Ratio OP:TP – – 0.78 0.78 Mean (mg/L) 0.30 0.23 0.38 0.35 Little Arkansas River at Sample Number 12 11 49 72 Valley Center (SC282) Samples > RL (%) 100 73 60 67 Mean Ratio OP:TP 0.46 0.42 0.61 0.56 Definition: – - No data.

Orthophosphate is detected throughout each stations’ respective period of record with OP concentrations consistently exceeding the reporting limit of 0.25 mg/L after 2002 (Figure 23). All stations in the watershed are influenced by municipal point source dischargers which may partially account for the high OP detection rates. The highest single OP concentration of 1.3 mg/L was detected at Kisiwa Creek near Halstead (SC703) in July 2014. At main stem stations, OP concentrations are consistently lower and detected throughout all flow ranges (Figure 24). This wide range of scatter, particularly at higher flows, indicates that diffuse sources of OP may also be prevalent in these watersheds.

Figure 23. Orthophosphate samples measuring greater than the reporting limit by station for the Little Arkansas River Watershed, February 8, 1995 to September 17, 2019.

Figure 24. Orthophosphate versus percent flow exceedance by station for the Little Arkansas River Watershed, February 8, 1995 to September 17, 2019.

Total Suspended Solids Phosphorus has a high affinity for fixation in soils, where it is adsorbed from soil solution. Erosion of phosphorus-laden soil particles is a common means for phosphorus to enter streams, where it is then desorbed. This natural propensity for adsorbtion and desorbtion to soil particles creates a positively correlated relationship between TP and TSS that is evident at the main stem stations in the watershed (Figures 25 and 26). When displayed by flow range, correlations are strongest for high flow conditions, indicating the influence of nonpoint and runoff sources of TP during high flows. Correlations for TP and TSS are weakest for low flow conditions, when the influence of municipal point source effluent is strongest; during these conditions, stream TP concentrations increase irrespective of TSS concentrations due to the contribution of TP concentrations from the effluent discharge. Trends in tributaries are not displayed due to small sample sizes.

Figure 25. Total phosphorus versus total suspended solids and total phosphorus versus total suspended solids by percent flow exceedance for the Little Arkansas River at Alta Mills (SC246).

Figure 26. Total phosphorus versus total suspended solids and total phosphorus versus total suspended solids by percent flow exceedance for the Little Arkansas River at Valley Center (SC282).

Total Phosphorus and Biological Indicators The narrative criteria of the Kansas Surface Water Quality Standards are based on conditions of the prevailing biological community. Excessive primary productivity may be indicated by extreme shifts in dissolved oxygen (DO), dissolved oxygen saturation (DO saturation), and pH as the chemical reactions of photosynthesis and respiration alter the ambient levels of oxygen and acid-base balance of the stream. These shifts, in turn, can result in undesirable regime shifts in the algal biomass and biological community within the stream.

Dissolved Oxygen At all SC stations for the watershed, dissolved oxygen and temperature are inversely related (Figures 27 to 29). This corresponds to seasonal changes in DO and temperature, where low mean DO concentrations occur in spring and summer-fall when temperatures are highest, and high mean DO concentrations occur in winter when temperatures are lowest (Table 13). This relationship is expected because oxygen becomes less soluble in water as temperatures increase. Additionally, although DO exhibits a diel trend due to daily fluctuations in photosynthetic activity, most samples from these stations were collected in the morning, reducing this variability in the datasets.

All stations in the watershed have violated the Kansas water quality criterion of 5.0 mg/L DO. The main stem station Little Arkansas River at Alta Mills (SC246) has the most exceedances (eight) and Little Arkansas River at Valley Center (SC282) has the least (two). However, there have been no exceedances at Little Arkansas River at Alta Mills (SC246) since 2012 and no

Figure 27. Dissolved oxygen and the relationship between dissolved oxygen and temperature for the Little Arkansas River at Alta Mills (SC246).

Figure 28. Dissolved oxygen and the relationship between dissolved oxygen and temperature for the Little Arkansas River at Valley Center (SC282).

Figure 29. Dissolved oxygen and the relationship between dissolved oxygen and temperature for the tributaries to the Little Arkansas River Watershed.

exceedances at Little Arkansas River at Valley Center (SC282) since 2003. Despite the unimpaired status of the main stem stations, the tributaries are all impaired for DO. Black Kettle Creek near Halstead (SC705) has five excursions from 1995 to 2018; Kisiwa Creek near Halstead (SC703) has four excursions from 1998 to 2018; and Emma Creek near Sedgwick (SC534) has three excursions from 1990 to 2010.

Dissolved Oxygen Saturation Primary productivity increases in the spring and summer-fall, when temperatures are higher and DO concentrations are lower. When primary productivity is excessive, oxygen from aquatic photosynthesis can create DO concentrations that exceed the natural oxygen equilibrium of the stream at a given temperature. The stream is considered supersaturated with oxygen when the expected versus actual DO concentrations exceed a DO saturation of 110%. Because of the system’s diel characteristics, supersaturated conditions are more likely to be detected in the afternoon when photosynthesis and temperatures are at their peak. In accordance with this, there are five detections above supersaturation among all the stations, four of which occurred in late morning or afternoon (Figures 30 to 32). Low DO saturation at these stations is reflected in the mean DO saturations for the stations, the highest of which is 82% at Little Arkansas River at Valley Center (SC282; Table 13).

Table 13. Mean temperature, dissolved oxygen, and dissolved oxygen saturation, as well as median pH, by season for the Little Arkansas River Watershed.

Station Spring Summer-fall Winter All Seasons

Temperature (°C) Little Arkansas River at Alta Mills (SC246) 18 21 5.5 14 Black Kettle Creek near Halstead (SC705) 18 21 7.4 16 Kisiwa Creek near Halstead (SC703) 21 23 5.0 17 Emma Creek near Sedgwick (SC534) 19 20 5.2 13 Little Arkansas River at Valley Center (SC282) 18 21 5.5 14 Dissolved Oxygen (mg/L) Little Arkansas River at Alta Mills (SC246) 7.0 6.8 11 8.5 Black Kettle Creek near Halstead (SC705) 5.8 5.5 8 6.5 Kisiwa Creek near Halstead (SC703) 5.0 5.6 9 6.4 Emma Creek near Sedgwick (SC534) 6.8 6.9 11 8.6 Little Arkansas River at Valley Center (SC282) 7.7 7.1 11 8.9 Dissolved Oxygen Saturation (%) Little Arkansas River at Alta Mills (SC246) 74 76 84 79 Black Kettle Creek near Halstead (SC705) 60 61 69 63 Kisiwa Creek near Halstead (SC703) 55 65 69 63 Emma Creek near Sedgwick (SC534) 71 74 85 78 Little Arkansas River at Valley Center (SC282) 81 79 86 82 pH Little Arkansas River at Alta Mills (SC246) 7.7 7.8 7.8 7.8 Black Kettle Creek near Halstead (SC705) 7.1 7.0 7.5 7.1 Kisiwa Creek near Halstead (SC703) 7.0 6.9 7.3 7.1 Emma Creek near Sedgwick (SC534) 7.8 7.6 7.9 7.8 Little Arkansas River at Valley Center (SC282) 7.8 7.7 7.8 7.7

pH Another water quality indicator of primary productivity is pH because photosynthesis can increase pH by removing carbon dioxide from the water. The Kansas numeric water quality criteria for pH is a range from 6.5 to 8.5. None of the stations in the watershed have pH values less than 6.5 or greater than 8.5. However, the main stem stations both indicate that pH is declining in their watersheds (Figures 31 and 32). The tributary stations do not have a clear trend, but Emma Creek near Sedgwick (SC534) consistently has the highest pH of the tributaries, with a median of 7.8 (Figure 33; Table 13). Median pH remains relatively consistent among all stations, ranging from 6.9 to 7.9 throughout the seasons. The main stem stations maintain the most consistency throughout all seasons, but the pH for the tributaries is highest in the winter.

Figure 30. Dissolved oxygen saturation and pH for the Little Arkansas River at Alta Mills (SC246).

Figure 31. Dissolved oxygen saturation and pH for the Little Arkansas River at Valley Center (SC282).

Figure 32. Dissolved oxygen saturation and pH for the tributaries to the Little Arkansas River Watershed.

Algal Biomass Chlorophyll-a is a photosynthetic pigment found in algae, and its concentration is commonly used as a measure of the algal biomass present in streams. Because nutrients directly influence primary production, the U.S. Environmental Protection Agency (USEPA) guidance on nutrient criteria for streams establishes a chlorophyll-a concentration range of 8 to 15 micrograms per liter (μg/L) before overall biology can become adversely impacted (U.S. Environmental Protection Agency, 2000). The only chlorophyll-a sample collected within the watershed is from West Emma Creek (SPB486); it was collected in 2015 with a concentration of 7.79 μg/L. While this single sample is below USEPA guidance, it is not feasible to infer concentrations or trends in other tributaries or the main stem Little Arkansas River from this sample.

Biological Community Biological data regarding macroinvertebrate organisms and community are collected at KDHE SP stations and stream biology (SB) stations. Macroinvertebrate organisms have been collected at two SP stations within the watershed monitored by Emma Creek near Sedgwick (SC534), one SP station within the watershed monitored by Little Arkansas River at Valley Center (SC282), and one SB station within the watershed monitored by Little Arkansas River at Valley Center (SC282). Both SP and SB stations have been assessed using the Aquatic Life Use Support (ALUS) Index as described in Kansas’ 2020 303(d) Methodology. The ALUS Index score consists of five categorizations of biotic conditions: 1. Macroinvertebrate Biotic Index (MBI): A statistical measure that evaluates the effects of nutrients and oxygen demanding substances on aquatic and semi-aquatic

maroinvertebrates based on the relative abundance of certain indicator taxa that is specific to the level of order and family. 2. Kansas Biotic Index for Nutrients (KBI-N): A statistical measure mathematically equivalent to the MBI that is restricted to aquatic insect macroinvertebrates and is species specific. 3. Ephemeroptera, Plecoptera, and Trichoptera (EPT): A measure of the richness of the intolerant aquatic EPT taxa wihin a macroinvertebrate sample used to evaluate the diversity within the sample. 4. EPT Percent of Count (EPT% CNT): The percentage of individuals belonging to the EPT orders in a sample of macroinvertebrates. 5. Shannon’s Evenness (SHN EVN): A measure of diversity that describes how evenly distributed the numbers of individuals are among the taxa in a sample.

These metrics are used to establish a score (Table 14) which is then translated into an indication of the biotic condition and support category available for aquatic life in the stream (Table 15).

Table 14. Aquatic Life Use Support Index metrics with scoring ranges and standardized scores. MBI KBI-N EPT EPT% CNT SHN EVN Score ≤ 4.18 ≤ 2.52 ≥ 16 ≥ 65 ≥ 0.849 4 4.19-4.38 2.53-2.64 14-15 56-64 0.826-0.848 3 4.39-4.57 2.65-2.75 12-13 48-55 0.802-0.825 2 4.58-4.88 2.76-2.87 10-11 38-47 0.767-0.801 1 ≥ 4.89 ≥ 2.88 ≤ 9 ≤ 37 ≤ 0.766 0

Table 15. Aquatic Life Use Support (ALUS) Index score range, interpretation of biotic condition, and aquatic life support category.

ALUS Index Score Biotic Condition Support Category

> 16-20 Very Good Supporting > 13-16 Good > 6-13 Fair Partially Supporting > 3-6 Poor Non-supporting 0-3 Very Poor

Stream probabilistic station locations vary on an annual basis and biotic samples are collected once per year for each station; therefore, samples from these stations cannot indicate changes in aquatic life trends over time for a specific location. However, the samples do offer general insight about the biotic conditions of the streams within watersheds. For the watershed monitored by Emma Creek near Sedgwick (SC534), West Emma Creek (SPB486) and Middle Emma Creek (SPB662) have one biology sample collected in 2015 and 2017, respectively (Table 16). The biotic conditions for both samples are considered very poor to poor and are non-supporting of aquatic life. For the watershed monitored by the Little Arkansas River at Valley Center (SC282), the Little Arkansas River (SPA475) was sampled for biology in 2009. The biotic condition for this station is considered fair and is partially supporting of aquatic life.

Unlike SP stations, SB stations are routinely sampled at a fixed location on an annual basis and can be assessed for changes in trends over time. The Little Arkansas River (SB727), which is upstream of the Little Arkansas River (SPA475), has been sampled annually since 2013 (except for 2016). This station has a mean ALUS Index score of 4, indicating that its biotic condition is poor and non-supporting of aquatic life. Individual samples collected at this station have never scored higher than 7 for the ALUS Index, and biotic conditions are typically listed as very poor for this station.

Table 16. Mean Aquatic Life Use Support (ALUS) Index scores for the Little Arkansas River Watershed. Stream Mean Stream Number Biology/ Period of ALUS Biotic ALUS Index Chemistry of Probabilistic Record Index Condition Support Category Station Samples Station Score Emma Creek SPB486 2015 1 4 Poor Non-supporting near Sedgwick SPB662 2017 1 0 Very Poor Non-supporting (SC534) Little Arkansas SB727 2013 to 2018 5 4 Poor Non-supporting River at Valley Center (SC282) SPA475 2009 1 11 Fair Partially Supporting

Implied Load Capacity - Desired Endpoints for Water Quality Little Arkansas River Watershed Ultimately, the implied load capacity and desired water quality endpoints of this TMDL will be to achieve the Kansas Water Quality Standards by eliminating the impacts to aquatic life, domestic water supply, and contact recreation associated with excessive phosphorus and objectionable flora as described in the narrative criteria pertaining to nutrients. As there are currently no existing numeric phosphorus criteria in Kansas, narrative criteria will be applied through endpoints for Little Arkansas River at Alta Mills (SC246), Black Kettle Creek near Halstead (SC705), Kisiwa Creek near Halstead (SC703), Emma Creek near Sedgwick (S534), and Little Arkansas River at Valley Center (SC282).

Current USEPA nutrient philosophy is predicated upon 25th percentile stream TP concentrations in an ecoregion with minimally impacted stream conditions (in the absence of reference stream conditions). This generalization is not tied to specific biological conditions; rather, it represents water quality protection policy guiding USEPA’s administration of clean water programs. The current TMDL lies within USEPA ecoregion South Central Cultivated Great Plains (V), and the suggested 25th percentile TP reference benchmark for streams within this ecoregion is 0.067 mg/L (U.S. Environmental Protection Agency, 2001). Assessment of 129 KDHE SC stations within the Level III Ecoregion Central Great Plains (27) with TP data from 2000 to April 2018 indicates a 25th percentile of medians of 0.130 mg/L and a 50th percentile of medians of 0.200 mg/L (Figure 33; Table 17).

Figure 33. U.S. Environmental Protection Agency Level III Ecoregions and Kansas Department of Health and Environment stream chemistry stations.

Table 17. Summary of Kansas Department of Health and Environment (KDHE) stream chemistry stations within the Level III Ecoregion from 2000 to April 2018. Number 25th Percentile 50th Percentile 75th Percentile USEPA Level III Sample of KDHE of Medians of Medians of Medians Ecoregion Number Stations (mg/L) (mg/L) (mg/L) Central Great Plains (27) 129 7,248 0.130 0.200 0.374

There are 19 KDHE stations with biology and chemistry data within the Level III Ecoregion Central Great Plains (27). An analysis of the mean ALUS Index versus the median TP concentration indicates that there is generally a decline in biology with increasing TP concentrations (Figure 34). There are two SB stations fully supporting biology that are unimpaired for TP, and the remaining unimpaired stations are partially supporting biology. This variability in relationship of the mean ALUS Index versus the median TP concentration is due to the numerous factors impacting biological health. Such variability supports an adaptive management approach to reduce current TP concentrations and loads rather than establishing a single, definitive threshold. Therefore, this TMDL seeks to establish an adaptive management approach through phased TP milestones; attainment of a milestone will elicit monitoring for biological improvement. As such, the primary measure of phosphorus load reduction in the TMDL for the Little Arkansas River Watershed will be an improved ALUS Index. An ALUS Index score greater than 13 at the SB station will serve to establish that the biological community reflects recovered or renewed diversity and minimal disruption by the impacts on aquatic life as described in the narrative criteria for nutrients.

Figure 34. Aquatic Life Use Support (ALUS) Index versus median total phosphorus for stream biology and stream chemistry stations within the Level III Ecoregion from 1990 to 2016.

Furthermore, secondary indicators of the health of the aquatic biological community will be assessed at the SC station. The chlorophyll-a concentration will serve as an additional biological measure of nutrient loading reduction in order to assess improvements in primary productivity and address its impacts on aquatic life, recreation, and domestic water supply as described in the narrative criteria for nutrients. Dissolved oxygen concentrations will be monitored to ensure concentrations are greater than 5.0 mg/L. According to the Kansas Water Quality Standards, concentrations below this are low enough to put aquatic life under stress. Dissolved oxygen saturation will also be monitored for indication of overactive primary productivity, as indicated by supersaturated values greater than 110%. The pH will be monitored, as well, to ensure that overactive primary productivity is not altering stream chemistry; values should remain between 6.5 and 8.5 in order to protect aquatic life according to the Kansas Water Quality Standards.

The numeric endpoints indicating attainment of water quality standards within the watershed for stream segments in this TMDL, as measured at Little Arkansas River at Alta Mills (SC246), Black Kettle Creek near Halstead (SC705), Kisiwa Creek near Halstead (SC703), Emma Creek near Sedgwick (S534), and Little Arkansas River at Valley Center (SC282), are: 1. An ALUS Index score greater than 13 at SB stations. 2. Median sestonic chlorophyll-a concentrations less than or equal to 10 µg/L at SC stations. 3. Dissolved oxygen concentrations greater than 5.0 mg/L at SC stations. 4. Dissolved oxygen saturation less than 110% at SC stations. 5. Values within the range of 6.5 to 8.5 for pH at SC stations.

As there are currently no numeric phosphorus criteria in Kansas, the series of endpoints established by this TMDL will be the measure used to indicate full support of aquatic life, domestic water supply, and contact recreation in the Little Arkansas River Watershed. All five endpoints must initially be maintained over three consecutive years to constitute full support of the designated uses of the impaired stream segments in this TMDL, as measured at the KDHE stations Little Arkansas River at Alta Mills (SC246), Black Kettle Creek near Halstead (SC705), Kisiwa Creek near Halstead (SC703), Emma Creek near Sedgwick (S534), and Little Arkansas River at Valley Center (SC282). Attainment of the DO endpoint over three consecutive years at the tributary stations Black Kettle Creek near Halstead (SC705), Kisiwa Creek near Halstead (SC703), and Emma Creek near Sedgwick (S534) constitutes a restoration of DO within these watersheds, and they will be considered for DO delisting.

These endpoints will be evaluated periodically as phosphorus levels decline in the watershed, with achievement of the ALUS Index endpoint indicating the restored status of the aquatic life use in the river and its tributaries. Simultaneous achievement of the chlorophyll-a, DO, DO saturation, and pH endpoints will signal that TP reductions are addressing the accelerated succession of aquatic biota and the development of objectionable concentrations of algae and algae by-products, thereby restoring the contact recreation and domestic water supply uses in the river and its tributaries. After the endpoints are attained, simultaneous digression of these endpoints more than once every three years on average constitutes a resumption of the TP impairment at these stations.

This TMDL establishes an adaptive management approach for TP through phased TP management milestones (Table 18). The Phase I milestone will be a TP concentration of 0.200 mg/L, reflecting the 50th percentile of medians for KDHE SC stations within the Level III Ecoregion. Total phosphorus concentrations approaching the Phase I milestone will cue the examination for altered, improved biological conditions at the Little Arkansas River SB station (SB727) as well as other potential biological sites within the watershed. Should aquatic life not respond, a Phase II milestone will commence with a TP concentration of 0.130 mg/L, reflecting the 25th percentile of medians for KDHE SC stations within the Level III Ecoregion.

Table 18. Current total phosphorus (TP) condition from 2000 to 2019 and Phase I and II TP milestones for stations in the Little Arkansas River Watershed. Current Condition Phase I Phase II Station (2000-2018) Median TP TP Milestone TP Reduction TP Milestone TP Reduction (mg/L) (mg/L) (%) (mg/L) (%) Little Arkansas River at 0.513 0.200 61 0.130 75 Alta Mills (SC246) Black Kettle Creek near 1.04 0.200 81 0.130 88 Halstead (SC705) Kisiwa Creek near 1.39 0.200 86 0.130 91 Halstead (SC703)

Current Condition Phase I Phase II Station (2000-2018) Median TP TP Milestone TP Reduction TP Milestone TP Reduction (mg/L) (mg/L) (%) (mg/L) (%) Emma Creek near 0.574 0.200 65 0.130 77 Sedgwick (SC534) Little Arkansas River at 0.558 0.200 64 0.130 77 Valley Center (SC282)

3. SOURCE INVENTORY AND ASSESSMENT

The Little Arkansas River Watershed is comprised of the tributary watersheds Black Kettle Creek near Halstead (SC705), Kisiwa Creek near Halstead (SC703), and Emma Creek near Sedgwick (SC534) and the main stem watersheds Little Arkansas River at Alta Mills (SC246) and Little Arkansas River at Valley Center (SC282; Figure 35). These watersheds are predominantly within Harvey, Marion, McPherson, Reno, Rice, and Sedgwick counties. Within this section, point sources, livestock, land use, water diversions, population, on-site waste systems, and contributing runoff are considered by watershed and county.

Point Sources There are a total of 24 National Pollution Discharge Elimination System (NPDES) permitted facilities within the Little Arkansas River Watershed (Table 19). Of the 24 permitted facilities, six are located in the Little Arkansas River at Alta Mills (SC246) Watershed, three are located in the Black Kettle Creek near Halstead (SC705) Watershed, four are located in the Kisiwa Creek near Halstead (SC703) Watershed, seven are located in the Emma Creek near Sedgwick (SC534) Watershed, and four are located in the Little Arkansas River at Valley Center (SC282) Watershed. Additionally, there is one Municipal Separate Storm Sewer System (MS4) permit within the Little Arkansas River Watershed.

Dischargers to the Little Arkansas River at Alta Mills (SC246) Watershed Of the six permits located within the Little Arkansas River at Alta Mills (SC246) Watershed, there is one non-discharging lagoon, four discharging lagoons, and one municipal mechanical WWTP.

The non-discharging lagoon is operated by Reno County Sewer District #8. This facility operates a four-cell lagoon that receives septic tank effluent pumping. Additionally, it is authorized to irrigate as needed. This system is prohibited from discharging, does not monitor for TP, and is not expected to contribute to the TP impairment in the watershed.

The four discharging lagoons are operated by the cities of Geneseo, Inman, Little River, and Windom. The cities of Geneseo and Windom operate three-cell lagoon systems, and the cities of Inman and Little River operate four-cell lagoon systems. The cities of Geneseo, Inman, and Windom are required to monitor for TP quarterly, and the City of Little River is required to

Figure 35. Map of contributing area and facilities for Little Arkansas River Watershed.

monitor for TP monthly. The City of Little River is allowed to irrigate as necessary. According to the facility’s discharge monitoring record (DMR) for the period of record September 2008 to December 2019, the City of Geneseo discharged to the Little Arkansas River during approximately 9% of the quarters. The City of Geneseo has not recorded TP concentrations from their discharge since it began monitoring in 2018 because the facility has not discharged since 2015. According to the facility’s DMR for the period of record July 2004 to December 2019, the City of Inman discharged to Blaze Fork Creek during approximately 41% of the quarters. The City of Inman has reported TP concentrations since November 2014 and currently discharges a mean TP concentration of 1.44 mg/L. According to the facility’s DMR for the period of record July 2004 to December 2019, the City of Little River discharged to the Little Arkansas River during approximately 82% of the quarters. The City of Little River has reported TP concentrations since October 2010 and currently discharges a mean TP concentration of 2.68 mg/L. According to the facility’s DMR for the period of record May 2015 to December 2019, the City of Windom discharged to the Little Arkansas River via an unnamed tributary during approximately 32% of the quarters. The City of Windom has reported TP concentrations since May 2015 and currently discharges a mean TP concentration of 1.83 mg/L. The discharging lagoons for the cities of Geneseo, Inman, Little River, and Windom will be assigned TP wasteload allocations (WLAs) under this TMDL.

The municipal mechanical WWTP is operated by the City of Buhler. According to the city’s DMR for the period of record October 2004 to December 2019, this facility currently operates at 0.133 million gallons per day (MGD). The WWTP is not designed for nutrient removal but can optimize performance to improve nutrient removal. The City of Buhler WWTP discharges to the Little Arkansas River and currently has a monthly monitoring requirement for TP. From 2004 to 2019, the discharge from this facility has a mean TP concentration of 2.13 mg/L, or 2.37 pounds per day (lbs/day). The municipal mechanical WWTP operated by the City of Buhler will be assigned a TP WLA under this TMDL.

Dischargers to the Black Kettle Creek near Halstead (SC705) Watershed Of the three permits located within the Black Kettle Creek near Halstead (SC705) Watershed, there is one non-discharging lagoon, one industrial pretreatment facility, and one discharging lagoon.

The non-discharging lagoon is operated by Gardenview Mennonite Church. This facility operates a one-cell lagoon. The system is prohibited from discharging, does not monitor for TP, and is not expected to contribute to the TP impairment in the watershed.

The industrial pretreatment facility is operated by Moridge Manufacturing, Inc. This facility generates wastewater from metal finishing operations and discharges to the City of Moundridge WWTP. Prior to discharge, this facility is required to meet pretreatment standards for metal finishing. Total phosphorus from the pretreatment facility’s discharge is accounted for within the NPDES permit for the City of Moundridge.

The combined discharging lagoon and mechanical WWTP are operated by the City of Moundridge. Recent upgrades to this facility installed a mechanical WWTP that discharges into the lagoon system. The city continues to operate the four-cell lagoon system that discharges to Little Arkansas River via the tributary Black Kettle Creek. According to the facility’s DMR for the period of record July 2004 to December 2019, the City of Moundridge discharged during approximately 97% of the quarters. The City of Moundridge is required to monitor for TP monthly and has reported TP since January 2013. The facility currently discharges a mean TP concentration of 3.56 mg/L. The WWTP for the City of Moundridge will be assigned a TP WLA under this TMDL.

Dischargers to the Kisiwa Creek near Halstead (SC703) Watershed Of the four permits located within the Kisiwa Creek near Halstead (SC703) Watershed, there are two non-discharging lagoons, a surface water treatment plant, and a discharging lagoon.

The two non-discharging lagoons are operated by Reno County Blue Spruce Sewer District #3 and #10 and Victory Village. Reno County Blue Spruce Sewer District #3 and #10 operates a three-cell lagoon that is allowed to irrigate as necessary and Victory Village operates a two-cell lagoon. The lagoon for Reno County Blue Spruce Sewer District #3 and #10 is considered temporary and must be discontinued when city service becomes available. These systems are prohibited from discharging, do not monitor for TP, and are not expected to contribute to the TP impairment in the watershed.

The surface water treatment plant is operated by the Wichita ASR Phase I Treatment Plant. The Wichita ASR Phase I Treatment Plant is an aquifer storage and recovery facility that withdraws water from the Little Arkansas River during high flows. This water is treated and injected into the aquifer. Off-specification treated water that is not suitable for injecting is stored in a lagoon and discharged to Kisiwa Creek; however, sediment slurry may be discharged to the Little Arkansas River. No discharge has occurred at this facility to date but it is required to monitor for TP annually when discharging. The surface water treatment plant for the Wichita ASR Phase I Treatment Plant will be assigned a TP WLA under this TMDL.

The discharging lagoon is operated by City of Burrton. The City of Burrton operates a four-cell lagoon system that discharges to Kisiwa Creek via the North Branch Kisiwa Creek. According to the facility’s DMR for the period of record April 2004 to December 2019, the City of Burrton discharged during approximately 57% of the quarters. This facility is required to monitor for TP quarterly and has reported TP since March 2011. The facility currently discharges a mean TP concentration of 4.25 mg/L. The discharging lagoon for the City of Burrton will be assigned a TP WLA under this TMDL.

Dischargers to the Emma Creek near Sedgwick (SC534) Watershed Of the seven permits located within the Emma Creek near Sedgwick (SC534) Watershed, there are two non-discharging lagoons, one pretreatment facility, one concrete plant, one discharging lagoon, one industrial mechanical WWTP, and one municipal mechanical WWTP.

The two non-discharging lagoons are operated by Cook's Mobile Home Court and MJ's Truck Repair LLC. Cook's Mobile Home Court operates a two-cell lagoon and MJ's Truck Repair LLC operates a one-cell lagoon. The lagoon for MJ's Truck Repair LLC is considered temporary and must be discontinued when city service becomes available. These systems are prohibited from discharging, do not monitor for TP, and are not expected to contribute to the TP impairment in the watershed.

The industrial pretreatment facility is operated by Excel Industries, Inc. This facility generates wastewater from metal finishing operations and discharges to the City of Hesston WWTP. Prior to discharge, this facility is required to meet pretreatment standards for metal finishing. Total phosphorus from the pretreatment facility’s discharge is accounted for within the NPDES permit for the City of Hesston.

The concrete plant is operated by Builders Concrete & Supply/Hesston. This facility is a permanent concrete operation that generates wastewater by washing trucks into a one-cell basin that can overflow. This system does not monitor for TP and is not expected to contribute to the TP impairment in the watershed.

The discharging lagoon is operated by the City of Goessel. This facility operates a four-cell lagoon system that discharges to Emma Creek via the tributary Middle Emma Creek. According to the facility’s DMR for the period of record July 2004 to October 2019, the City of Goessel discharged during approximately 95% of the quarters. The City of Goessel is required to monitor for TP quarterly and has reported TP since May 2013. The facility currently discharges a mean

TP concentration of 1.56 mg/L. The discharging lagoon for the City of Goessel will be assigned a TP WLA under this TMDL.

The industrial mechanical WWTP is operated by AGCO Corporation. According to the facility’s DMR for the period of record June 2004 to December 2019, it currently operates at 0.105 MGD. The AGCO Corporation WWTP discharges to the Little Arkansas River via the tributary Middle Emma Creek and currently has a monthly monitoring requirement for TP. From 2004 to 2019, the discharge from this facility has a mean TP concentration of 4.26 mg/L, or 3.74 lbs/day. The industrial mechanical WWTP operated by AGCO Corporation will be assigned a TP WLA under this TMDL.

The municipal mechanical WWTP is operated by the City of Hesston. According to the city’s DMR for the period of record August 2004 to December 2019, this facility currently operates at 0.419 MGD. The WWTP is not designed for nutrient removal but can optimize performance to improve nutrient removal and irrigate wastewater at a golf course as necessary. The City of Hesston WWTP discharges to Middle Emma Creek and currently has a monthly monitoring requirement for TP. From 2007 to 2019, the discharge from this facility has a mean TP concentration of 2.85 mg/L, or 9.98 lbs/day. The municipal mechanical WWTP operated by the City of Hesston will be assigned a TP WLA under this TMDL.

Dischargers to the Little Arkansas River at Valley Center (SC282) Watershed Of the four permits located within the Little Arkansas River at Valley Center (SC282) Watershed, there are two non-discharging lagoons, one surface water treatment plant, and one municipal mechanical WWTP.

The two non-discharging lagoons are operated by KDOT - Harvey County Rest Stop and Spring Lakes Resort. KDOT - Harvey County Rest Stop operates a four-cell lagoon and Spring Lakes Resort operates a three-cell lagoon that is authorized to irrigate adjacent grassland as necessary. These systems are prohibited from discharging, do not monitor for TP, and are not expected to contribute to the TP impairment in the watershed.

The surface water treatment plant is operated by Wichita ASR Phase II Treatment Plant. The Wichita ASR Phase II Treatment Plant operates in conjunction with the Wichita ASR Phase I Treatment Plant to withdraw water from the Little Arkansas River during high flows and inject treated water into aquifer storage. Water that is not suitable for injecting is pumped to a recharge basin and eventually discharged back to the Little Arkansas River. According to the facility’s DMR for the period of record July 2012 to December 2019, the Wichita ASR Phase II Treatment Plant currently discharges 0.204 MGD. This facility is not required to monitor for TP. However, according to water quality samples collected by the USGS from this facility’s discharge (375348097262800) for the period of record April 2012 to September 2019, the Wichita ASR Phase II Treatment Plant discharges a TP concentration of 2.61 mg/L, or 4.4 lbs/day. The Wichita ASR Phase II Treatment Plant will be assigned a TP WLA under this TMDL.

The municipal mechanical WWTP is operated by the City of Halstead. According to the city’s DMR for the period of record August 2004 to December 2019, this facility currently operates at 0.129 MGD. The WWTP is not designed for nutrient removal but can optimize performance to

improve nutrient removal. In order to accomplish this, facility operators have met with a state contractor to improve operations. The City of Halstead WWTP discharges to the Little Arkansas River and currently has a monthly monitoring requirement for TP. From 2004 to 2019, the discharge from this facility has a mean TP concentration of 4.78 mg/L, or 5.2 lbs/day. The municipal mechanical WWTP operated by the City of Halstead will be assigned a TP WLA under this TMDL.

Table 19. National Pollution Discharge Elimination System (NPDES) facilities in the Little Arkansas River Watershed. Current Kansas NPDES Current Total Treatment/ Receiving Permit Monitoring Permittee Permit Permit Flow Phosphorus Facility Type Stream Expiration Frequency Number Number (MGD) Mean (mg/L) Little Arkansas River at Alta Mills (SC246) Reno Co. Sewer M-AR49- KSJ00 Non-discharging May 31, District #8 NO08 0699 Lagoon NA 2023 NA 0 NA

City of Geneseo M-LA04- KS009 Discharging Little December Quarterly – – OO02 8175 Lagoon Arkansas R 31, 2022 M-LA08- KS008 Discharging Blaze Fork June 30, City of Inman Quarterly – 1.44 OO01 0292 Lagoon Cr 2021 M-LA10- KS008 Discharging Little Renewal City of Little River Monthly – 2.68 OO02 5758 Lagoon Arkansas R Pending M-LA18- KS005 Discharging Little June 30, City of Windom Quarterly – 1.83 OO01 1721 Lagoon Arkansas R 2022 M-LA01- KS002 Mechanical Little October City of Buhler Monthly 0.133 2.13 OO01 7553 WWTP Arkansas R 31, 2022 Black Kettle Creek near Halstead (SC705) Gardenview C-LA06- KSJ00 Non-discharging November NA NA 0 NA Mennonite Church NO03 0565 Lagoon 30, 2022 City of Moridge P-LA12- KSP00 Industrial March 31, Moundridge NA – – Manufacturing, Inc. OO01 0088 Pretreatment 2025 WWTP Discharging City of M-LA12- KS002 Lagoon and Black December Monthly – 3.56 Moundridge OO01 1008 Mechanical Kettle Cr 31, 2022 WWTP Kisiwa Creek near Halstead (SC703) Reno Co. Blue M-AR49- KSJ00 Non-discharging December Spruce Sewer NA NA 0 NA NO03 0453 Lagoon 31, 2023 District #3 and #10 C-AR49- KSJ00 Non-discharging April 30, Victory Village NA NA 0 NA NO01 0599 Lagoon 2023 Surface Water Kisiwa Cr Wichita ASR Phase I-LA02- KS009 Treatment Plant December and Little Annually – – I Treatment Plant PO02 9392 – Discharging 31, 2022 Arkansas R Lagoon

Current Kansas NPDES Current Total Treatment/ Receiving Permit Monitoring Permittee Permit Permit Flow Phosphorus Facility Type Stream Expiration Frequency Number Number (MGD) Mean (mg/L) M-LA02- KS004 Discharging December City of Burrton Kisiwa Cr Quarterly – 4.25 OO01 9786 Lagoon 31, 2020 Emma Creek near Sedgwick (SC534) Cook's Mobile C-LA07- KSJ00 Non-discharging May 31, NA NA 0 NA Home Court NO01 0199 Lagoon 2021 MJ's Truck Repair C-LA12- KSJ00 Non-discharging January NA NA 0 NA LLC NO01 0566 Lagoon 31, 2021 City of Excel Industries, P-LA07- KSP00 Industrial June 30, Hesston NA – – Inc. IO01 0046 Pretreatment 2024 WWTP Builders Concrete I-LA07- KSG11 Opossum September Concrete Plant NA – – & Supply/Hesston PR01 0032 Cr 30, 2022 M-LA05- KS008 Discharging Middle September City of Goessel Quarterly – 1.56 OO02 1060 Lagoon Emma Cr 30, 2022 Industrial I-LA07- KS008 Middle August AGCO Corporation Mechanical Monthly 0.105 4.26 PO02 0951 Emma Cr 31, 2023 WWTP M-LA07- KS002 Mechanical Middle May 31, City of Hesston Monthly 0.419 2.85 OO01 2799 WWTP Emma Cr 2022 Little Arkansas River at Valley Center (SC282) KDOT - Harvey M-LA13- KSJ00 Non-discharging November NA NA 0 NA Co. Rest Stop NO01 0383 Lagoon 30, 2021 Spring Lakes C-LA06- KSJ00 Non-discharging November NA NA 0 NA Resort NO02 0564 Lagoon 30, 2021 Wichita ASR Phase I-LA24- KS009 Surface Water Little July 31, NA 0.204 2.61 II Treatment Plant PO01 9694 Treatment Plant Arkansas R 2025 M-LA06- KS002 Mechanical Little October City of Halstead OO01 6263 WWTP Arkansas R 31, 2022 Monthly 0.129 4.78 Definitions: NA - not applicable; – - data not available

Minor and Major Municipal Point Source Dischargers The analyses in Section 2 indicate that there are dominant point sources contributing to TP loads in the Little Arkansas River Watershed. The City of Buhler operates a minor WWTP that discharges to the Little Arkansas River at Alta Mills (SC246) Watershed. From 2004 to 2019, this WWTP has discharged a consistent volume but has decreased the TP concentrations present in its discharge since 2012 (Figure 36). The City of Hesston operates a major WWTP that discharges to the Emma Creek near Sedgwick (SC534) Watershed. This facility has steadily increased its discharge since 2016 (Figure 37); however, since 2016, TP concentrations in the discharge have decreased sharply. The City of Halstead operates a minor WWTP that discharges to the Little Arkansas River at Valley Center (SC282) Watershed. From 2004 to 2019, the WWTP has decreased its discharge volume but the TP concentrations present in its discharge have increased since 2011 (Figure 38).

Figure 36. Monthly total phosphorus and discharge from the City of Buhler Wastewater Treatment Plant (NPDES permit # KS0027553), October 2004 to December 2019.

Figure 37. Monthly total phosphorus and discharge from the City of Hesston Wastewater Treatment Plant (NPDES permit # KS0022799), August 2004 to December 2019.

Figure 38. Monthly total phosphorus and discharge from the City of Halstead Wastewater Treatment Plant (NPDES permit # KS0026263), June 2004 to December 2019.

Municipal Separate Storm Sewer System Discharge There is one MS4 permit within the Little Arkansas River Watershed (Table 20). This permit authorizes the City of Hutchinson to discharge stormwater. Under this permit, the city is expected to develop a Stormwater Management Plan (SMP) and implement Best Management Practices (BMPs) to the maximum extent practicable within its jurisdiction in order to reduce pollutant loading to waterbodies during rainfall events.

Table 20. National Pollution Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System permit in the Little Arkansas River Watershed. Permitee Kansas Permit Number NPDES Permit Number Permit Expiration City of Hutchinson M-AR49-SN01 KSR440009 October 31, 2024

Livestock and Waste Management Systems There are 92 certified or permitted Animal Feeding Operations (AFOs) and Concentrated Animal Feeding Operations (CAFOs) within the Little Arkansas River Watershed. Of these, 31 are located in the Little Arkansas River at Alta Mills (SC246) Watershed, none are located in the Black Kettle Creek (SC705) and Kisiwa Creek (SC703) near Halstead watersheds, 43 are located in the Emma Creek near Sedgwick (SC534) Watershed, and 18 are located in the Little Arkansas River at Valley Center (SC282) Watershed (Table 21). There are four CAFOs large enough to require a federal permit, one in the Little Arkansas River at Alta Mills (SC246) Watershed (A- LARN-H002/KS0098680), one in the Emma Creek near Sedgwick (SC534) Watershed (A-

LAHV-H002/KS0094331), and two in the Little Arkansas River at Valley Center (SC282) Watershed (A-LAHV-C003/KS0085863 and A-LAHV-H001/KS0093785).

In addition to certified or permitted AFOs and CAFOs, there are unregistered operations below the permitting threshold in the Little Arkansas River Watershed. While these operations are smaller than AFOs and CAFOs, they are unregulated and can graze cattle which have access to in-stream watering. As such, these facilities may contribute to TP loading in the watershed.

All permitted livestock facilities have waste management systems designed to retain an anticipated two weeks of normal wastewater from their operations and contain a 25-year, 24- hour rainfall/runoff event. A rainfall event of this magnitude would coincide with streamflow that occurs less than 1 to 5% of the time. Additionally, facility waste management systems are designed to minimize runoff entering operations and detain runoff emanating from operations. It is unlikely TP loading would be attributable to properly operating permitted facilities, though extensive loading may occur if any of these facilities were in violation and discharged.

The total number of livestock within the counties in this watershed is approximately 500,000 head (Table 22; U.S. Department of Agriculture, 2019). The primary livestock industry in this region is cattle, with cattle and calves accounting for approximately 325,000 head. From 2012 to 2017, livestock production increased by 17% in the counties. The greatest change in livestock is in poultry and hogs and pigs. In Harvey and McPherson counties, poultry production has increased by over 1000%. In Harvey, Marion, and Reno counties, hogs and pigs production has increased by 15 to 77%.

Table 21. Certified or permitted Animal Feeding Operations and Concentrated Animal Feeding Operations in the Little Arkansas River Watershed. Kansas Permit Number County Livestock Type Livestock Total Little Arkansas River at Alta Mills (SC246) A-ARRC-S007 Rice Swine 2,700 A-LAHV-BA16 Harvey Beef 500 A-LAMP-B001 McPherson Beef 600 A-LAMP-B002 McPherson Beef 915 A-LAMP-B008 McPherson Beef 160 A-LAMP-BA01 McPherson Beef 700 A-LAMP-BA02 McPherson Beef 250 A-LAMP-BA04 McPherson Beef 100 A-LAMP-BA05 McPherson Beef 400 A-LAMP-BA10 McPherson Beef 20 A-LAMP-BA11 McPherson Beef 200 A-LAMP-BA12 McPherson Beef 200 A-LAMP-BA18 McPherson Beef 147 A-LAMP-BA22 McPherson Beef 200 A-LAMP-CA01 McPherson Beef 1,000 A-LAMP-FA01 McPherson Beef/Chickens 33,000

Kansas Permit Number County Livestock Type Livestock Total Little Arkansas River at Alta Mills (SC246) Continued A-LAMP-FA03 McPherson Chickens 27,400 A-LAMP-FA04 McPherson Turkeys 7,000 A-LAMP-M005 McPherson Dairy 336 A-LAMP-M028 McPherson Dairy 310 A-LAMP-S025 McPherson Swine 2,000 A-LAMP-T001 McPherson Truckwash 0 A-LARC-B001 Rice Beef 999 A-LARC-BA01 Rice Beef 100 A-LARC-MA01 Rice Dairy 40 A-LARC-S005 Rice Swine 4,086 A-LARC-S006 Rice Swine 3,690 A-LARC-T001 Rice Truckwash 0 A-LARN-BA01 Reno Beef 30 A-LARN-H002 Reno Swine 5,400 N-LAMP-6197 McPherson Dairy 300 Emma Creek near Sedgwick (SC534) A-LAHV-B006 Harvey Beef 200 A-LAHV-B007 Harvey Beef 300 A-LAHV-BA05 Harvey Beef 100 A-LAHV-BA08 Harvey Beef 20 A-LAHV-BA11 Harvey Beef 200 A-LAHV-BA23 Harvey Beef 960 A-LAHV-BA24 Harvey Beef 950 A-LAHV-FA02 Harvey Laying Hens 17,900 A-LAHV-FA03 Harvey Turkeys 6,500 A-LAHV-H002 Harvey Swine 4,200 A-LAHV-M010 Harvey Dairy 470 A-LAHV-S037 Harvey Swine 9,600 A-LAMN-B001 Marion Beef 800 A-LAMN-B002 Marion Beef 750 A-LAMN-BA01 Marion Beef 200 A-LAMN-S001 Marion Swine 3,000 A-LAMP-B005 McPherson Beef 999 A-LAMP-B006 McPherson Beef 200 A-LAMP-B007 McPherson Beef 999 A-LAMP-BA03 McPherson Beef 250 A-LAMP-BA06 McPherson Beef 300 A-LAMP-BA07 McPherson Beef 100 A-LAMP-BA08 McPherson Beef 75 A-LAMP-BA09 McPherson Beef 150

Kansas Permit Number County Livestock Type Livestock Total Emma Creek near Sedgwick (SC534) Continued A-LAMP-BA13 McPherson Beef 60 A-LAMP-BA14 McPherson Beef 75 A-LAMP-BA16 McPherson Beef 500 A-LAMP-BA19 McPherson Beef 150 A-LAMP-BA21 McPherson Beef 999 A-LAMP-FA02 McPherson Laying Hens 16,000 A-LAMP-M033 McPherson Dairy/Swine 65 A-LAMP-PA01 McPherson Turkeys 6,500 A-LAMP-S026 McPherson Beef/Swine 2,439 A-LAMP-S031 McPherson Swine 965 A-LAMP-S037 McPherson Swine 2,400 A-NEMP-BA02 McPherson Beef/Horses 520 A-WAHV-BA11 Harvey Beef 500 A-ARRN-BA09 Reno Beef 500 A-ARRN-M050 Reno Dairy 60 A-LAHV-B005 Harvey Beef 800 A-LAHV-S039 Harvey Beef/Swine 500 A-LAHV-F004 Harvey Turkeys 7,000 A-LAMP-S028 McPherson Sheep/Swine 660 Little Arkansas River at Valley Center (SC282) A-LAHV-B009 Harvey Beef 1,001 A-LAHV-BA09 Harvey Beef 500 A-LAHV-BA14 Harvey Beef 340 A-LAHV-BA15 Harvey Beef 350 A-LAHV-BA18 Harvey Beef 25 A-LAHV-BA20 Harvey Beef 950 A-LAHV-BA21 Harvey Beef 500 A-LAHV-C003 Harvey Beef 1,500 A-LAHV-F005 Harvey Turkeys 7,300 A-LAHV-H001 Harvey Swine 4,800 A-LAHV-M008 Harvey Dairy/Swine 293 A-LAHV-S003 Harvey Beef/Swine 1,200 A-LAHV-S005 Harvey Beef/Swine 1,048 A-LAHV-S020 Harvey Swine 400 A-LAHV-S033 Harvey Swine 1,800 A-LAHV-S034 Harvey Swine 1,500 A-LAHV-SA04 Harvey Beef/Swine 450 A-LAHV-T001 Harvey Truckwash 6 Definition: Bold – Federally permitted.

Table 22. Agricultural census results for livestock by county from 2012 and 2017 (U.S. Department of Agriculture, 2012 and 2019). Percent Change (%), Livestock Total, 2012 Total, 2017 2012 to 2017 Harvey Cattle and Calves 35,702 38,572 8 Sheep and Lambs 547 2,199 302 Poultry 1,297 33,554 2,487 Hogs and Pigs 12,989 18,084 39 Goats 439 331 -25 Marion Cattle and Calves 96,938 71,819 -26 Sheep and Lambs 1,199 789 -34 Poultry 4,522 3,692 -18 Hogs and Pigs 6,947 12,323 77 Goats 698 1,020 46 McPherson Cattle and Calves 39,083 37,676 -4 Sheep and Lambs 2,448 3,120 27 Poultry 2,655 38,940 1,367 Hogs and Pigs 16,939 14,316 -15 Goats 431 634 47 Reno Cattle and Calves 79,307 86,985 10 Sheep and Lambs 3,396 3,100 -9 Poultry 7,657 5,331 -30 Hogs and Pigs 14,191 16,288 15 Goats 1,221 1,386 14 Rice Cattle and Calves 48,298 60,616 26 Sheep and Lambs 325 774 138 Poultry – – – Hogs and Pigs 13,473 13,646 1 Goats 308 240 -22 Sedgwick Cattle and Calves 29,784 29,054 -2 Sheep and Lambs 3,034 1,287 -58 Poultry 2,330 4,300 85 Hogs and Pigs 1,990 – – Goats 819 726 -11 Definition: – - No data.

Land Use Throughout the six counties, there is a total of 4,980 farms and over 2 million acres of cropland (Table 23; U.S. Department of Agriculture, 2019). From 2012 to 2017, the number of farms in cropland has decreased by 6% and the number of acres in cropland has increased by 2%. Rice and Marion counties have the greatest decline in farms, with a decrease of 14%. McPherson has the greatest increase in cropland acres, with an increase of 17%.

Table 23. Agricultural census results for farms and cropland by county from 2012 and 2017 (U.S. Department of Agriculture, 2012 and 2019). County Year Total Farms in Cropland Total Cropland (acres) 2017 642 297,922 Harvey 2012 638 297,248 Percent Change (%), 2012 to 2017 1 0 2017 768 334,705 Marion 2012 890 341,358 Percent Change (%), 2012 to 2017 -14 -2 2017 710 267,510 McPherson 2012 783 228,383 Percent Change (%), 2012 to 2017 -9 17 2017 1,334 590,749 Reno 2012 1,404 591,675 Percent Change (%), 2012 to 2017 -5 0 2017 397 366,052 Rice 2012 462 360,927 Percent Change (%), 2012 to 2017 -14 1 2017 1,129 408,872 Sedgwick 2012 1,127 395,977 Percent Change (%), 2012 to 2017 0 3

The 2011 National Land Cover Database indicates the dominant land use in the watershed is cultivated crops, with 63% of the watershed currently used for crop cultivation (Table 24; Figure 39). Cultivated cropland has an increased potential for nutrient runoff from fertilizers contributing to TP loads in the watershed. Grassland, including pastureland and hay fields, is the second most prevalent land use in the watershed, with 26% of the watershed in grassland.

Table 24. Data from the 2011 National Land Cover Database for land cover by percent in the Little Arkansas River Watershed. Land Use (percent) Open Water Developed Barren Forest Grassland Cultivated Crops Wetlands 1 6 0 3 26 63 1

Figure 39. The 2011 National Land Cover Database map for land cover in the Little Arkansas River Watershed.

Diversions Among the six counties there are more than 10,000 permitted diversions which diverted approximately 300,000 acre-feet of water in 2017 (Water Information Management and Analysis System, 2019). Groundwater is the dominant source of water, accounting for 86% of all diverted water in 2017 (Figure 40). During dry years, such as 2012, consumption of groundwater increases by 19% when compared to years with normal conditions, such as 2017. The predominant use for diverted water in this region is irrigation which accounted for nearly 200,000 acre-feet of diverted water in 2017. Secondary diversion uses across the counties include municipal, industrial, and recreational uses.

The six counties have an approximate total of 946,000 acres of irrigated land as of 2017, a decrease of 7% since 2012 (Table 26; U.S. Department of Agriculture, 2012 and 2019). Reno County has the most irrigated acres (approximately 249,000) but has decreased its irrigated land by 17% since 2012. Marion County has the least irrigated acres (approximately 32,000) and has decreased its irrigated acreage by 14% since 2012.

Figure 40. Diverted water by use according to the Water Information Management and Analysis System (WIMAS) for counties in the Little Arkansas River Watershed.

Table 25. Agricultural census results for irrigated land by county from 2012 and 2017 (U.S. Department of Agriculture, 2012 and 2019). Irrigated Land (acres), Irrigated Land (acres), Percent Change (%), County 2012 2017 2012 to 2017 Harvey 137,484 138,657 1 Marion 36,642 31,659 -14 McPherson 194,497 189,892 -2 Reno 299,456 248,981 -17 Rice 169,578 181,884 7 Sedgwick 184,537 154,929 -16 Total 1,022,194 946,002 -7

The U.S. Department of Agriculture collects census data for the cost of fertilizer, lime, and soil conditioners applied to agricultural land (Table 26). Overall, the cost of fertilizer, lime, and soil conditioners within the counties totaled approximately $93 million in 2017, a 21% decrease since 2012. From 2012 to 2017, all counties in the watershed have reduced expenditures for fertilizer, lime, and soil conditioners by 11 to 27%.

Table 26. Agricultural census results for cost of fertilizer, lime, and soil conditioners by county from 2012 and 2017 (U.S. Department of Agriculture, 2012 and 2019). Fertilizer Cost ($), Fertilizer Cost ($), Percent Change (%), County 2012 2017 2012 to 2017 Harvey 18,491,000 13,920,000 -25 Marion 17,123,000 13,015,000 -24 McPherson 24,349,000 17,769,000 -27 Reno 24,303,000 21,588,000 -11 Rice 15,066,000 12,152,000 -19 Sedgwick 19,156,000 14,611,000 -24 Total 118,488,000 93,055,000 -21

Population Density According to the 2010 U.S. Census, the total population within the six counties is approximately 649,000 and has increased by 8% since 2000 (Table 27). Harvey and Sedgwick counties have the greatest population increases, with 6 and 10% increases, respectively. The largest city within the Little Arkansas River Watershed is Hutchinson, which had an approximate population of 42,000 in 2010 and has increased its population by 3% from 2000 to 2010.

Table 27. City and county census results from 2000 and 2010 (U.S. Census Bureau, 2010). Population Change, Location Population, 2000 Population, 2010 2000 to 2010 (%) Harvey County 32,869 34,684 6 Burrton 932 901 -3 Halstead 1,873 2,085 11 Hesston 3,509 3,709 6 Sedgwick 1,537 1,695 10 Marion County 13,361 12,660 -5 Goessel 565 539 -5 McPherson County 29,554 29,180 -1 Canton 829 748 -10 Inman 1,142 1,377 21 Moundridge 1,593 1,737 9 Windom 137 130 -5 Reno County 64,790 64,511 0 Buhler 1,358 1,327 -2 Hutchinson 40,787 42,080 3 Rice County 10,761 10,083 -6 Geneseo 272 267 -2 Little River 536 557 4 Sedgwick County 452,869 498,365 10 Valley Center 4,883 6,822 40

On-Site Waste Systems The populations of Harvey, McPherson, Reno, and Sedgwick counties are predominantly urban, with 56 to 92% of their populations classified as urban (Table 28; U.S. Census Bureau, 2010). The populations of Marion and Rice counties are more rural, with 78 and 64% of their populations classified as rural, respectively. Urban populations are typically served by municipal sewer systems; however, rural populations do not have access to this service and use septic systems. According to the U.S. Environmental Protection Agency’s Spreadsheet Tool for Estimating Pollutant Load (STEPL), there are a total of 3,218 septic systems located in the Little Arkansas River Watershed. Septic systems in the state of Kansas typically have an estimated 10- 15% failure rate (Electric Power Research Institute, 2000). Failing on-site septic systems have the potential to contribute to nutrient loading in the watershed. However, because of their small flows and the proclivity of phosphorus to adsorb to soil, failing on-site septic systems are considered a minor source of TP loading within the watershed and are not expected to significantly contribute to TP impairment in the Little Arkansas River.

Table 28. Census results by urban and rural population and county from 2010 (U.S. Census Bureau, 2010). County Classification Population, 2010 Percent (%) Rural 10,724 31 Harvey Urban 23,960 69 Rural 9,845 78 Marion Urban 2,815 22 Rural 12,692 44 McPherson Urban 16,488 56 Rural 20,191 31 Reno Urban 44,320 69 Rural 6,431 64 Rice Urban 3,652 36 Rural 38,168 8 Sedgwick Urban 460,197 92

Contributing Runoff Runoff conditions causing overland flow can occur as a result of either infiltration-excess (precipitation exceeds the infiltration rate of the soil) or saturation-excess (precipitation falls on soils saturated due to an elevated water table; Juracek, 2000). Overland flow can impact the quality of water entering streams, thereby impacting water-quality loads. Soil permeability categories in Kansas have been defined by the following criteria in inches per hour (in/hr): very high (3.43 in/hr), high (2.86 in/hr), moderate (2.29 in/hr), low (1.71 in/hr), very low (1.14 in/hr), and extremely low (0.57 in/hr).

According to the Natural Resources Conservation Service (NRCS) State Soil Geographic Database (STATSGO), the Little Arkansas River Watershed has a soil permeability range of 0.01 to 17.3 in/hr (Figure 41). Within the Little Arkansas River Watershed, 72% of the watershed has a soil permeability rate greater than 3.43 in/hr, placing it in the extremely high soil permeability category.

Figure 41. Map of Natural Resources Conservation Service State Soil Geographic Database soil permeability in the Little Arkansas River Watershed.

Background Levels Phosphorus is present over the landscape and in the soil profile. It is also present in terrestrial and aquatic biota. Wildlife can contribute to phosphorus loadings, particularly if they congregate to a density that exceeds the assimilative capacity of the land or water.

4. ALLOCATION OF POLLUTANT REDUCTION RESPONSIBILITY

The following TMDLs, or load capacities (LC), are based upon the desired endpoints for aquatic life condition, chlorophyll-a concentration, dissolved oxygen concentration, dissolved oxygen saturation, and pH. All endpoints should improve to a level that provides full attainment of designated uses as phosphorus concentrations decrease in the Little Arkansas River and its tributaries. The LCs are based on TP management milestones and the incremental flow conditions at each station. Incremental flow conditions were calculated using a watershed ratio for the KDHE SC station contributing area and the USGS streamgages. Incremental flow conditions are presented for each station within the Little Arkansas River Watershed to account for contributions originating within each watershed. While the tributaries Turkey Creek near Alta

Mills (SC533) and Sand Creek near Sedgwick (SC535) have approved TP TMDLs, their loads are not addressed by this TMDL.

Load Capacity This TMDL is established in two phases to reduce TP concentrations and loadings within the watershed; it will require periodic assessment of aquatic life conditions to determine compliance with the narrative nutrient criteria as TP concentrations and loadings decline. The Phase I TP milestone is set at 0.200 mg/L, the 50th percentile of the median concentrations of KDHE SC stations within the Level III Ecoregion. Presuming one or more of the endpoints are not met at the end of Phase I, Phase II will commence with a TP milestone of 0.130 mg/L, the 25th percentile of the median concentrations of KDHE SC stations within the Level III Ecoregion. Further reductions in TP concentrations and loads for Phase II will be accomplished through enhanced implementation of controls on both point and nonpoint sources in the watershed. For both Phase I and Phase II, total LCs are calculated according to the previously described TP milestones and the flow conditions in the Little Arkansas River Watershed.

For purposes of comparing current TP loading conditions in the river to the expected reduction in TP loading, the current condition was evaluated using the median TP concentration from 2000 to 2019. Sampled TP concentrations were then converted to loads for seasonal comparison.

Wasteload Allocations The total Phase I TP WLA for point sources for the Little Arkansas River Watershed is 51.2 lbs/day (Table 29). The reduced TP WLA for Phase II for the watershed is 43.2 lbs/day. The TP WLAs in this TMDL are calculated using concentrations for each facility according to the following: non-discharging lagoons and industrial pretreatment facilities are not assigned a TP concentration; the concrete operation WLA is calculated at a TP concentration of 0 mg/L; discharging lagoons are calculated at a TP concentration of 2 mg/L, an effluent concentration common in Kansas lagoons; the industrial mechanical WWTP and the surface water treatment plants are calculated at their currently discharged mean TP concentrations; and municipal mechanical WWTPs are calculated at a Phase I TP concentration of 1 mg/L and a Phase II TP concentration of 0.5 mg/L. The TP WLAs assigned to all municipal facilities are based upon current design flows for each facility. The TP WLA assigned to the industrial mechanical WWTP and the Wichita ASR surface water treatment plants are based upon their current mean flow, if available; if mean flow is unavailable for these facilities, permitted design flow is used.

For Phase I and Phase II in each watershed, the non-discharging lagoons have no WLA assigned to them. The industrial pretreatment facilities in the Black Kettle Creek near Halstead (SC705) and Emma Creek near Sedgwick (SC534) watersheds are not assigned a TP concentration as their discharge is accounted for within the NPDES permit for the respective facility receiving its discharge. For Phase I and Phase II, the concrete operation in the Emma Creek near Sedgwick (SC534) Watershed is assigned a WLA of 0 lbs/day.

Little Arkansas River at Alta Mills (SC246) Watershed The municipal discharging lagoons for the cities of Geneseo, Inman, Little River, and Windom are assigned TP WLAs in accordance with the previously described method. Accordingly, the Phase I and Phase II TP WLA assigned to the City of Geneseo lagoon is 0.35 lbs/day or 128

lbs/year; the City of Inman lagoon is 2.21 lbs/day or 805 lbs/year; the City of Little River lagoon is 1.69 lbs/day or 618 lbs/year; and the City of Windom lagoon is 0.46 lbs/day or 168 lbs/year. The Phase I TP WLA assigned to the WWTP operated by the City of Buhler, which has a design flow of 0.168 MGD, is 1.40 lbs/day or 512 lbs/year.

Black Kettle Creek near Halstead (SC705) Watershed The municipal discharging lagoon for the City of Moundridge is assigned a Phase I and Phase II TP WLA of 5.33 lbs/day or 1,944 lbs/year.

Kisiwa Creek near Halstead (SC703) Watershed The Wichita ASR Phase I Treatment Plant is assigned a Phase I and Phase II TP WLA of 8.35 lbs/day or 3,049 lbs/year. The municipal discharging lagoon for the City of Burrton is assigned a Phase I and Phase II TP WLA of 2.59 lbs/day or 945 lbs/year.

Emma Creek near Sedgwick (SC534) Watershed The municipal discharging lagoon for the City of Goessel is assigned a Phase I and Phase II TP WLA of 1.55 lbs/day or 567 lbs/year. The Phase I and Phase II TP WLA assigned to the WWTP operated by AGCO Corporation, which has a mean flow of 0.105 MGD, is 3.74 lbs/day or 1,364 lbs/year. The Phase I TP WLA assigned to the WWTP operated by the City of Hesston, which has a design flow of 1.3 MGD, is 10.9 lbs/day or 3,964 lbs/year.

Little Arkansas River at Valley Center (SC282) Watershed The Wichita ASR Phase II Treatment Plant is assigned a Phase I and Phase II TP WLA of 4.45 lbs/day or 1,623 lbs/year. The Phase I TP WLA assigned to the WWTP operated by the City of Halstead, which has a design flow of 0.420 MGD, is 3.51 lbs/day or 1,281 lbs/year.

Table 29. Phase I total phosphorus wasteload allocations for discharging National Pollution Discharge Elimination System (NPDES) permitted facilities for the Little Arkansas River Watershed. * No design flow established by NPDES permit. Anticipated TP Daily TP Annual NPDES Design TP Wasteload Kansas Permit Treatment/Facility Wasteload Wasteload Permittee Permit Flow Allocation Number Type Allocation Allocation Number (MGD) Concentration (lbs/day) (lbs/year) (mg/L) City of Geneseo M-LA04-OO02 KS0098175 Discharging Lagoon 0.021 2 0.35 128 City of Inman M-LA08-OO01 KS0080292 Discharging Lagoon 0.132 2 2.21 805 City of Little M-LA10-OO02 KS0085758 Discharging Lagoon 0.1014 2 1.69 618 River City of Windom M-LA18-OO01 KS0051721 Discharging Lagoon 0.0275 2 0.46 168 City of Buhler M-LA01-OO01 KS0027553 Mechanical WWTP 0.168 1 1.40 512 TP Wasteload Allocation for Little Arkansas River at Alta Mills (SC246) 6.11 2,230 Discharging Lagoon City of M-LA12-OO01 KS0021008 and Mechanical 0.3188 2 5.33 1,944 Moundridge WWTP TP Wasteload Allocation for Black Kettle Creek near Halstead (SC705) 5.33 1,944

Anticipated TP Daily TP Annual NPDES Design TP Wasteload Kansas Permit Treatment/Facility Wasteload Wasteload Permittee Permit Flow Allocation Number Type Allocation Allocation Number (MGD) Concentration (lbs/day) (lbs/year) (mg/L) Wichita ASR Surface Water Phase I I-LA02-PO02 KS0099392 Treatment Plant – 0.5 2 8.35 3,049 Treatment Plant Discharging Lagoon City of Burrton M-LA02-OO01 KS0049786 Discharging Lagoon 0.155 2 2.59 945 TP Wasteload Allocation for Kisiwa Creek near Halstead (SC703) 10.9 3,993 City of Goessel M-LA05-OO02 KS0081060 Discharging Lagoon 0.093 2 1.55 567 AGCO Industrial I-LA07-PO02 KS0080951 0.105 4.26 3.74 1,364 Corporation Mechanical WWTP City of Hesston M-LA07-OO01 KS0022799 Mechanical WWTP 1.3 1 10.9 3,964 TP Wasteload Allocation for Emma Creek near Sedgwick (SC534) 16.2 5,909 Wichita ASR Surface Water Phase II I-LA24-PO01 KS0099694 3.02 2.61 4.45 1,623 Treatment Plant Treatment Plant City of Halstead M-LA06-OO01 KS0026263 Mechanical WWTP 0.420 1 3.51 1,281 Builders Concrete & I-LA07-PR01 KSG110032 Concrete Plant * 0 0 0 Supply TP Wasteload Allocation for Little Arkansas River at Valley Center (SC282) 7.96 2,905 TP Sub-watershed Total Wasteload Allocation 46.5 16,973 TP Total Reserve Wasteload Allocation 4.65 1,697 TP Total Wasteload Allocation 51.2 18,670

Reserve Wasteload Allocation A reserve WLA is calculated at 10% for the entirety of the Little Arkansas River Watershed in order to accommodate future development within the watershed. The Phase I WLA is 46.5 lbs/day, resulting in a reserve WLA of 4.65 lbs/day; the reserve WLA remains 4.65 lbs/day for Phase II WLA. The reserve WLA applies to the watershed terminus at Little Arkansas River at Valley Center (SC282) and may be apportioned throughout the Little Arkansas River Watershed.

Municipal Separate Storm Sewer System Wasteload Allocation Within the Little Arkansas River Watershed, an MS4 stormwater allocation is calculated for the City of Hutchinson in the Kisiwa Creek near Halstead (SC703) Watershed. The MS4 stormwater allocation is applied to the watershed terminus at the Little Arkansas River at Valley Center (SC282).

Based upon modeling completed with Wiki Watershed, stormwater discharge was estimated for calculating the MS4 stormwater allocation (Stroud Water Research Center, 2020). Estimated stormwater discharge, percent permittee development in the watershed, and percent of days with precipitation each year were used to calculate a daily TP load. The daily TP load was then divided by the LC remaining after accounting for WLAs and reserve WLAs for both Phase I and

Phase II. The resulting value is expressed as a percentage and applied to the LC remaining after accounting for WLAs and reserve WLAs in order to calculate MS4 stormwater allocations. The Phase I and Phase II TP MS4 stormwater allocation for the watershed is 6% with a reserve MS4 stormwater allocation of 5%. There are no nominal MS4 stormwater allocations assigned to the watershed because there is no available LC to allocate. Entities permitted for urban stormwater runoff are expected to implement BMPs, as prescribed in their MS4 permits, to the maximum extent practicable in order to reduce runoff and TP loading from developed areas.

Livestock All AFOs and CAFOs within the Little Arkansas River Watershed are assigned a WLA of 0 lbs/day.

Load Allocation The LA is established to account for nonpoint sources of TP in the watershed. The LA is the remainder of the LC after all other allocations are accounted for. Loads from nonpoint source TP are assumed to be minimal during low flow conditions and grow proportionately as flow conditions increase, thereby accounting for increased runoff during precipitation events. The application of agricultural BMPs in riparian zones near cropland and livestock areas should continue in order to abate and reduce nonpoint source TP loading in the Little Arkansas River Watershed.

Defined Margin of Safety The margin of safety safeguards against the uncertainty in TP loading in the Little Arkansas River. This TMDL incorporates conservative assumptions to establish an implicit margin of safety. First, five endpoints are established which must be met for three consecutive years before achieving attainment of the water quality standards. Second, concurrently reducing TP and nitrogen discharged from municipal WWTPs is emphasized in order to diminish the often synergistic effects these nutrients have on aquatic life. Third, design flows are used for all point source WLAs, despite the current operation of most facilities under design flow. Fourth, some facilities are assigned WLAs when it is likely that they do not contribute nutrient loads.

The described TMDLs, or LCs, are delineated below for the Little Arkansas River at Alta Mills (SC246; Figure 42; Table 30), Black Kettle Creek near Halstead (SC705; Figure 43; Table 31), Kisiwa Creek near Halstead (SC703; Figure 44; Table 32), Emma Creek near Sedgwick (SC534; Figure 45; Table 33), and Little Arkansas River at Valley Center (SC282; Figure 46; Table 34) watersheds.

Figure 42. Total phosphorus Phase I incremental Total Maximum Daily Load for the Little Arkansas River at Alta Mills (SC246).

Table 30. Incremental Phase I and Phase II current load conditions (based upon the median total phosphorus concentration from 2000 to 2019), total load capacity, and load capacity apportionment for the Little Arkansas River at Alta Mills (SC246). Flow Flow at Current Load Wasteload Load Exceedance Terminus Condition Capacity Allocation Allocation (%) (cfs) (lbs/day) (lbs/day) (lbs/day) (lbs/day) Phase I 90 2.32 6.41 2.50 2.50 0 75 5.90 16.3 6.37 6.11 0.26 50 12.2 33.7 13.2 6.11 7.09 25 35.2 97.4 38.0 6.11 31.89 10 175 484 189 6.11 182.89 Phase II 90 2.32 6.41 1.63 1.63 0 75 5.90 16.3 4.14 4.14 0 50 12.2 33.7 8.55 5.41 3.14 25 35.2 97.4 24.7 5.41 19.29 10 175 484 123 5.41 117.59

Figure 43. Total phosphorus Phase I incremental Total Maximum Daily Load for Black Kettle Creek near Halstead (SC705).

Table 31. Incremental Phase I and Phase II current load conditions (based upon the median total phosphorus concentration from 2000 to 2019), total load capacity, and load capacity apportionment for Black Kettle Creek near Halstead (SC705). Flow Flow at Current Load Wasteload Load Exceedance Terminus Condition Capacity Allocation Allocation (%) (cfs) (lbs/day) (lbs/day) (lbs/day) (lbs/day) Phase I 90 0.48 2.69 0.52 0.52 0 75 1.01 5.65 1.09 1.09 0 50 1.76 9.91 1.91 1.91 0 25 3.94 22.1 4.26 4.26 0 10 16.0 89.7 17.3 5.33 11.97 Phase II 90 0.48 2.69 0.34 0.34 0 75 1.01 5.65 0.71 0.71 0 50 1.76 9.91 1.24 1.24 0 25 3.94 22.1 2.77 2.77 0 10 16.0 89.7 11.2 5.33 5.87

Figure 44. Total phosphorus Phase I incremental Total Maximum Daily Load for the Kisiwa Creek near Halstead (SC703).

Table 32. Incremental Phase I and Phase II current load conditions (based upon the median total phosphorus concentration from 2000 to 2019), total load capacity, and load capacity apportionment for the Kisiwa Creek near Halstead (SC703). Reserve Flow Flow at Current Load Wasteload MS4 Load MS4 Exceedance Terminus Condition Capacity Allocation Allocation Allocation Allocation (%) (cfs) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) Phase I 90 1.58 11.9 1.71 1.71 0 0 0 75 3.33 25.1 3.60 3.60 0 0 0 50 5.86 44.1 6.33 6.33 0 0 0 25 12.7 96.0 13.8 10.9 0.28 0.28 2.34 10 52.0 392 56.2 10.9 1.12 1.12 43.06 Phase II 90 1.58 11.9 1.11 1.11 0 0 0 75 3.33 25.1 2.34 2.34 0 0 0 50 5.86 44.1 4.11 4.11 0 0 0 25 12.7 96.0 8.95 8.95 0 0 0 10 52.0 392 36.5 10.9 0.73 0.73 24.14

Figure 45. Total phosphorus Phase I incremental Total Maximum Daily Load for Emma Creek near Sedgwick (SC534).

Table 33. Incremental Phase I and Phase II current load conditions (based upon the median total phosphorus concentration from 2000 to 2019), total load capacity, and load capacity apportionment for the Emma Creek near Sedgwick (SC534). Flow Flow at Current Load Wasteload Load Exceedance Terminus Condition Capacity Allocation Allocation (%) (cfs) (lbs/day) (lbs/day) (lbs/day) (lbs/day) Phase I 90 2.05 6.36 2.22 2.22 0 75 3.51 10.9 3.79 3.79 0 50 5.63 17.5 6.08 6.08 0 25 11.4 35.3 12.3 12.3 0 10 44.2 137 47.8 16.2 31.6 Phase II 90 2.05 6.36 1.44 1.44 0 75 3.51 10.9 2.47 2.47 0 50 5.63 17.5 3.95 3.95 0 25 11.4 35.3 7.99 7.99 0 10 44.2 137 31.0 10.7 20.3

Figure 46. Total phosphorus Phase I incremental Total Maximum Daily Load for the Little Arkansas River at Valley Center (SC282).

Table 34. Incremental Phase I and Phase II current load conditions (based upon the median total phosphorus concentration from 2000 to 2019), total load capacity, and load capacity apportionment for the Little Arkansas River at Valley Center (SC282). Reserve Flow Flow at Current Load Wasteload Load Wasteload Exceedance Terminus Condition Capacity Allocation Allocation Allocation (%) (cfs) (lbs/day) (lbs/day) (lbs/day) (lbs/day) (lbs/day) Phase I 90 2.33 7.00 2.51 2.51 0 0 75 4.90 14.7 5.29 5.29 0 0 50 8.62 25.9 9.31 7.96 1.35 0 25 18.7 56.4 20.2 7.96 4.65 7.59 10 76.5 230 82.6 7.96 4.65 69.99 Phase II 90 2.33 7.00 1.63 1.63 0 0 75 4.90 14.7 3.44 3.44 0 0 50 8.62 25.9 6.05 6.05 0 0 25 18.7 56.4 13.2 6.20 4.65 2.35 10 76.5 230 53.7 6.20 4.65 42.85

Priority HUC12s While this watershed has several major and minor municipal point source dischargers, reductions in nonpoint sources from BMP implementation in HUC12s will be necessary to achieve the TMDL (Table 35; Figure 47). Priority HUC12s in this analysis are identified primarily by the percentage of cultivated crops in the HUC12. The Little Arkansas River Watershed consists of 25 HUC12s. According to STEPL, the Little Arkansas River Watershed high priority HUC12s are 110300120201, 110300120202, 110300120203, 110300120301, 110300120401, and 110300120402. Proactive entities may implement BMPs at any time, with an emphasis on priority HUC12s likely yielding the greatest nonpoint source TP reductions to the Little Arkansas River Watershed.

Table 35. Little Arkansas River Watershed HUC12s by total phosphorus load according to estimations from the Spreadsheet Tool for Estimating Pollutant Load. Land Area Total Phosphorus Total Yield Watershed (acres) (lbs/year) (lbs/year/acre) 110300120106 28,388 22,295 0.79 110300120304 20,680 16,555 0.80 110300120104 21,613 17,406 0.81 110300120107 22,624 26,674 1.18 110300120101 32,641 45,107 1.38 110300120502 20,303 29,403 1.45 110300120102 32,850 49,820 1.52 110300120103 31,172 48,224 1.55 110300120303 22,297 38,757 1.74 110300120305 27,534 53,688 1.95 110300120306 20,901 43,283 2.07 110300120105 34,402 74,959 2.18 110300120209 23,611 52,362 2.22 110300120403 38,432 85,838 2.23 110300120407 31,518 70,586 2.24 110300120408 26,119 58,889 2.25 110300120404 24,804 57,782 2.33 110300120307 18,671 44,295 2.37 110300120302 18,819 45,399 2.41 110300120201 26,557 68,166 2.57 110300120203 27,350 74,316 2.72 110300120202 20,751 57,858 2.79 110300120402 23,419 73,264 3.13 110300120401 29,062 91,388 3.14 110300120301 25,679 86,693 3.38 Definition: Bold – priority HUC12s

Figure 47. Map of priority HUC12s by total phosphorus load according to estimations from the Spreadsheet Tool for Estimating Pollutant Load for the Little Arkansas River Watershed.

State Water Plan Implementation Priority Due to the prevalence of high TP concentrations in the Little Arkansas River, this TMDL focuses on reducing TP loading to the watershed. Primary reductions in TP loadings will need to be achieved through effective riparian and land management. Due to the need to reduce the high nutrient loads in the Little Arkansas River, this TMDL will be High Priority for implementation.

Nutrient Reduction Framework Priority Ranking This watershed lies within the Little Arkansas Subbasin. This is a subbasin contributing to the Lower Arkansas River Basin (HUC8 11030012), which is among the top 16 HUC8s targeted for state action to reduce nutrients.

5. IMPLEMENTATION

Desired Implementation Activities 1. Make operational changes in municipal WWTPs to reduce the phosphorus load.

2. Facilitate wastewater reuse for treated municipal wastewater. 3. Renew state and federal permits and inspect permitted facilities for permit compliance. 4. Ensure proper on-site waste system operations in proximity to main stem and tributary segments. 5. Improve riparian conditions along stream systems by installing grass and/or forest buffer strips along the streams and drainage channels in the watershed. 6. Implement and maintain conservation farming practices—including conservation rotation, no-till farming, and contour farming—in order to reduce runoff and cropland erosion of agricultural areas in the watershed. 7. Perform extensive soil testing to ensure excess phosphorus is not unnecessarily applied. 8. Ensure labeled application rates for chemical fertilizers are followed to reduce runoff. 9. Encourage use of subsurface applications for fertilizer. 10. Implement nutrient management plans and ensure that land-applied manure is properly managed to reduce runoff. 11. Establish pasture management practices, including proper stock density, to reduce soil erosion and stormwater runoff. 12. Install alternative livestock watering systems and relocate livestock feeding areas away from riparian areas. 13. Establish alternative livestock foraging areas, collaborate with producers to develop areas for grazing cover crops, and implement rotational grazing systems. 14. Provide education and outreach opportunities on topics such as soil health, nutrient management, and livestock management. 15. Support BMP implementation efforts of the Little Arkansas River Watershed Restoration and Protection Strategy (WRAPS).

Implementation Program Guidance NPDES and State Permits – KDHE a. Continue to monitor influent to and effluent from the permitted discharging WWTPs, encourage wastewater reuse and irrigation disposal, and ensure compliance and proper operation of WWTPs to control phosphorus in wastewater effluent. b. Establish permit limits after 2021, as determined by KDHE, with the initial implementation of goals and appropriate schedules of compliance for permits issued prior. c. Manage the WLA for the watershed to accommodate growth as needed. d. Manure management plans, detailing proper land application rates and practices, will be implemented to prevent runoff of applied manure. e. Inspect permitted livestock facilities to ensure compliance. f. Apply pollution prevention technologies to newly registered livestock facilities with less than 300 animal units. g. Inspect newly permitted livestock facilities for integrity of applied pollution prevention technologies.

Nonpoint Source Pollution Technical Assistance – KDHE a. Provide technical assistance on practices to establish vegetative buffer strips.

b. Provide technical assistance on nutrient management for livestock facilities and practices which minimize impacts of small livestock operations in the watershed to reduce impacts to stream resources. c. Support implementation efforts of the Little Arkansas River WRAPS and incorporate long term objectives of this TMDL into their 9-element watershed plan.

Water Resource Cost Share and Nonpoint Source Pollution Control Program – Kansas Department of Agriculture-Division of Conservation (KDA-DOC) a. Apply conservation farming practices—including no-till, terraces, and contours—and erosion control structures, including sediment control basins and constructed wetlands. b. Provide sediment control practices to minimize erosion and sediment transport from cropland and grassland in the watershed. c. Encourage residue management to reduce phosphorus loss and transport from cropland runoff in the watershed. d. Implement manure management plans. e. Install livestock waste management systems for manure storage.

Riparian Quality Enhancement Initiative – KDA-DOC a. Protect, establish, or re-establish natural riparian systems, including tree/shrub stands and streambank vegetation. b. Develop riparian restoration projects along targeted stream segments, especially those areas with base flow. c. Promote wetland construction and protection to reduce runoff and assimilate loadings. d. Coordinate riparian management within the watershed and develop riparian restoration projects.

Extension Outreach and Technical Assistance – Kansas State University a. Educate agricultural producers on sediment, nutrient, and pasture management. b. Provide technical assistance on buffer strip design and minimizing cropland runoff. c. Encourage annual soil testing to determine capacity of field to hold phosphorus. d. Educate residents, landowners, and watershed stakeholders about nonpoint source pollution. e. Promote and utilize the WRAPS efforts for pollution prevention, runoff control, and resource management. f. Educate livestock producers on livestock waste management, land-applied manure applications, and nutrient management plans. g. Provide technical assistance on livestock waste management systems and nutrient management plans. h. Repair or replace failing septic systems which are located within 100 feet of the Little Arkansas River or its tributaries.

Timeframe for Implementation The WWTP for the cities of Buhler (KS0027553), Hesston (KS0022799), and Halstead (KS0026263) will be required to implement nutrient reduction strategies. Strategies should be

evaluated by 2021 with any necessary enhanced treatment initiated by the next permit starting in 2022. Rural runoff management should expand from 2021 to 2031 to ensure nutrients are addressed. Urban stormwater management should expand from 2021 to 2031 to ensure nutrients are addressed. The Little Arkansas River WRAPS group has been active in the watershed since 2004 and currently focuses on implementing BMPs for sediment and atrazine. The group coordinates with the City of Wichita, which assesses a developer fee that funds offsite BMP implementation for these pollutants. In tandem with sediment and atrazine reduction, these BMPs can be used for nutrient reduction. In addition to these efforts, the WRAPS group hosts informational and educational meetings targeting soil health, nutrient management, and livestock management throughout the watershed. Pollutant reduction practices should be installed within the priority subwatersheds after 2021 with follow-up implementation and monitoring continuing through 2031.

Targeted Participants The primary participant for implementation of this TMDL are the municipal WWTPs for the cities of Buhler (KS0027553), Hesston (KS0022799), and Halstead (KS0026263). The WWTP for the cities of Buhler (KS0027553) and Hesston (KS0022799) have reduced the TP concentrations in their discharge since 2012 and 2016, respectively; these facilities should continue to optimize facility performance. The City of Halstead WWTP (KS0026263) has consulted with a state contractor to optimize their plant and should continue to pursue improvements.

In addition to the municipalities, the Little Arkansas River WRAPS will be a participant for implementation of this TMDL. Agricultural operations immediately adjacent to the Little Arkansas River and its tributaries will be encouraged to implement appropriate practices to further reduce phosphorus loads. Watershed coordinators, conservation district personnel, and county extension agents should coordinate to assess possible nutrient sources adjacent to streams. Implementation activities to address nonpoint sources should focus on those areas with the greatest potential to impact nutrient loading to the river.

Targeted agricultural activities to focus attention toward include: 1. Denuded riparian vegetation and poor riparian areas along the stream. 2. Conservation compliance on highly erodible areas. 3. Unbuffered cropland adjacent to the stream. 4. Total row crop acreage and gully locations. 5. No till or residue management on cropland. 6. Increasing no-till and precision agricultural practices, including cover crops. 7. Sites where drainage runs through or adjacent to livestock areas. 8. Sites where livestock have full access to streams as their primary water supply.

Milestone for 2031 By 2031, advancement of necessary and appropriate measures to decrease phosphorus effluent from the municipal WWTPs should be implemented. Establishment and maintenance of agricultural BMPs should expand and continue from 2021 to 2031. The Little Arkansas River WRAPS is currently (2019) beginning a three-year funding cycle to mitigate nutrient and sediment loads to the watershed, as well. Targeted watersheds for nutrient reduction from

cropland and livestock BMPs within the Little Arkansas River Watershed 9-Element Plan include Emma Creek (Tier 1) and Black Kettle and Kisiwa creeks (Tier 2). By 2031, TP data from the stations Little Arkansas River at Alta Mills (SC246), Black Kettle Creek near Halstead (SC705), Kisiwa Creek near Halstead (SC703), Emma Creek near Sedgwick (SC534), and Little Arkansas River at Valley Center (SC282) should show indication of declining TP concentrations relative to the pre-2021 data.

Delivery Agents The primary delivery agents for program participation will be the municipal WWTPs, KDHE, and the Little Arkansas River WRAPS.

Reasonable Assurances Authorities The following authorities may be used to direct activities in the watershed to reduce pollution: 1. K.S.A. 65-164 and 165 empowers the Secretary of KDHE to regulate the discharge of sewage into the waters of the state. 2. K.S.A. 65-171d empowers the Secretary of KDHE to prevent water pollution and to protect the beneficial uses of the waters of the state through required treatment of sewage and established water quality standards and to require permits by persons having a potential to discharge pollutants into the waters of the state. 3. K.S.A. 2002 Supp. 82a-2001 identifies the classes of recreation use and defines impairment for streams. 4. K.A.R. 28-16-69 through 71 implements water quality protection by KDHE through the establishment and administration of critical water quality management areas on a watershed basis. 5. K.S.A. 2-1915 empowers the State Conservation Commission to develop programs to assist the protection, conservation, and management of soil and water resources in the state, including riparian areas. 6. K.S.A. 75-5657 empowers the State Conservation Commission to provide financial assistance for local project work plans developed to control nonpoint source pollution. 7. K.S.A. 82a-901, et. seq. empowers the Kansas Water Office to develop a state water plan directing the protection and maintenance of surface water quality for the waters of the state. 8. K.S.A. 82a-951 creates the State Water Plan Fund to finance the implementation of the Kansas Water Plan, including selected WRAPS. 9. The Kansas Water Plan provides the guidance to state agencies to coordinate programs intent on protecting water quality and to target those programs to geographic areas of the state for high priority in implementation.

Funding The State Water Plan annually generates $12-13 million and is the primary funding mechanism for implementing water quality protection and pollution reduction activities in the state through the Kansas Water Plan. The state water planning process, overseen by the Kansas Water Office, coordinates and directs programs and funding toward watershed and water resources by priority. Typically, the state allocates at least 50% of the fund to programs supporting water quality

protection. This watershed and its TMDL are located within a High Priority area and should receive support for pollution abatement practices that lower the loading of sediment and nutrients.

Effectiveness Use of Biological Nutrient Removal technology in WWTPs has been well established to reduce nutrients, including phosphorus, in wastewater. Agricultural nutrient control has proven effective through conservation tillage, contour farming, and use of grass waterways and buffer strips; additionally, the proper implementation of comprehensive livestock waste management plans has proven effective at reducing nutrient runoff associated with livestock facilities. Presuming the Phase I milestone is not met, this TMDL will be evaluated after 2031 to assess the reductions in phosphorus loads that have taken place with guidance provided to targeted participants regarding follow-up implementation activities.

6. MONITORING

Monitoring for TP will continue at KDHE stations Little Arkansas River at Alta Mills (SC246), Little Arkansas River at Valley Center (SC282), and additional tributary stations. Biological monitoring will continue for Little Arkansas River (SB727) and at additional stations within the Little Arkansas River Watershed in order to assess compliance with the narrative nutrient criteria in the river. Based on the sampling data, the status of the watershed will be re-evaluated during the Section 303(d) listing process in 2032.

7. FEEDBACK

Public Notice An active website is established at http://www.kdheks.gov/tmdl/planning_mgmt.htm to convey information to the public on the general establishment of TMDLs and to provide specific TMDLs by river basin. This TMDL was posted to the Lower Arkansas River Basin on this site on November 23, 2020 for public review.

Public Hearing A public hearing on this TMDL was held on December 9, 2020 Topeka, Kansas to receive public comments. No comments were received.

Milestone Evaluation In 2031, evaluation will be made as to the degree of implementation that occurred within the watershed. Subsequent decisions will be made through consultation with local stakeholders’ conservation districts and WRAPS team regarding implementation of nonpoint source reduction strategies and development of additional implementation strategies for the watershed.

Consideration for Section 303(d) Delisting The segments covered by this TMDL will be evaluated for delisting under Section 303(d) based on the monitoring data from 2021 to 2031. Therefore, the decision for delisting will ensue in the preparation for the 2032 Section 303(d) list. Should modifications be made to the applicable water quality criteria during the implementation period, consideration for delisting, desired endpoints of this TMDL, and implementation activities may be adjusted accordingly.

Incorporation into the TMDL Vision Process, Water Quality Management Plan, and the Kansas Water Planning Process Under the current version of the Kansas TMDL Vision Process, the next anticipated revision of this TMDL will be after 2032. The revision will emphasize further reduction of nutrients in wastewater discharged by NPDES facilities and further implementation of conservation activities. Recommendations for this TMDL will be considered in the Kansas Water Plan implementation decisions under the State Water Planning Process for fiscal years 2022 to 2032.

Developed: December 28, 2020

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