DIVISION OF AGRICULTURE RESEARCH & EXTENSION UJA--University of Arkansas System Agriculture and Natural Resources FSA9537 Nutrient oncentrations in Big reek orrelate to Regional Watershed Land Use James Burke In the Ozark Mountain karst region, nutrient concentrations in streams of the Buffalo, Program Associate Upper Illinois and Upper White River watersheds increase as the percent of land in pas- ture and urban use increases Averaged over the last three years, nutrient concentrations Andrew Sharpley in Big Creek above and below the C&H Farm are similar to concentrations found in other Professor watersheds where there is a similar amount of pasture and urban land use Larry Berry monitoring in the Buffalo River Program Associate Background Watershed. The location of these Land use within watersheds watersheds is shown in Figure 1. The Kris Brye influences the quantity and quality of relationships between stream nutrient concentrations and land use for the Professor water draining from a watershed. As land disturbance increases and use region are used to determine if a per- intensifies, there is a general increase mitted concentrated animal feeding Mike Daniels in stormwater runoff and nutrient operation (CAFO) in Big Creek Water- Professor inputs that leads to a greater poten- shed, a sub-watershed of the Buffalo tial for nutrient discharge to receiving River Watershed, has affected stream Ed Gbur waters. For instance, with urban water quality. Land use in these Professor growth, more impervious surfaces watersheds is given in Table 1. increase the flashiness of runoff, stream flows and wastewater treat- Nitrate-N, total N, dissolved P and Karl VanDevender ment discharge. Also, as areas of agri- total P concentrations have been mea- Professor cultural production grow, more fer - sured over varying periods during base tilizer is applied to achieve optimum flow at the outlet of sub-watersheds in Stephen King production. Thus, as the percent of a the Big Creek (two sites, 2 14 to 2 17), Principal Scientist, watershed drainage area in pasture, Buffalo (2 sites, 1985 to 2 17), Upper Illinois (29 sites, 2 9) and Upper Science and Technology row crop or urban use increases, there is a general increase in nutrient con- White River Watersheds (2 sites, 2 5 Facilities Council, centrations in storm and base flows. to 2 6) (Figure 1). Rutherford Appleton Laboratory In this fact sheet, we show the Data from Big Creek were paired effect of land use on nitrogen (N) and with discharge available from a gaging Phil Hays phosphorus (P) concentrations in station just downstream from the swine streams of the Ozark Highlands and CAFO, where the USGS developed the Professor Boston Mountains, northwest rating curve; discharge information was Arkansas, by combining previously only available from May 2 14 through Brian Haggard published data for the Upper Illinois December 2 17. The data were then River Watershed (Haggard et al., used to look at changes in flow-adjusted Professor [A] 2 1 ), Upper White River Watershed nutrient concentrations in Big Creek (Giovannetti et al., 2 13) and ongoing (White et al., 2 4). Arkansas Is ____________________ [A]Concentration is defined as the mass of a substance (M), such as a nutrient, over the Our Ca pus volume of water (V) in which it is contained, or C = M/V. “Flow-adjusted nutrient on entra- tions” – when looking at how concentrations change over time in streams, we have to consider how concentrations might also change with stream flow (volume of water) and not just change in mass; nutrient concentrations often have some type of relation to flow, maybe increasing or even decreasing Visit our web site at: as stream flow increases. We have to flow-adjust concentrations so we can remove the variability in https://www.uaex.uada.edu concentrations that flow might cause to see how things are changing over time. University of Arkansas, United States Department of Agriculture, and County Governments Cooperating Study Watersheds in the Ozark Highlands Ecoregion Big Creek Watershed N A Big Creek Wat ershed Wat ershed influen cing dow nstr eam sit e C- UpperWhlteR. Watershed S':-Upper llllnolaR . watershed C, BuffaloNattnoal R. Watershed "'- lluffalo­ BlgC- 8lruma BlgC---.ci 2 41cm DownsnamWll8rslled = u...-w.i.r.11ec1Credit: UIGS, ESRI,and NRCS .Mottitonng Slce-t ADEQ 0 I-IUC12: • Tribvta.rios USGS e ~- Tributar la ~ Whlle River Tribu:tiuies ._. Buffalo Ftlq r -­ llllnol s Rl'l'a-1....,,_ :lit Boavor Rc.s1Jrvlor 0510 20km Trlb\.lt:Jry$1-1b ,hcidi 0 I) ,! 10 20 km ~ KUC 12 Srit4• 0 CJ Subs hods ~ 0 S 10 20 kffl I J I I I I II t Big CrlMlk Wllhtq;IMtd :6 f'\ Uppcir llllooh Woatltfl,'.h,cd r';, C.~· Upper White Wiltc,-.hed fl Cf tl,fi, : uses. AOl;Q,, N"~,it Pt,rk Sttvl~ A Buffalo Rlver WaterslM!d l ~• CNdit ! USG$, ADEQ,. ftd AW.RC C~J..W RC Upper Illinois River Upper White River Buffalo River Watershed Watershed Watershed Figure . Location of the Big Creek, Buffalo River, Upper Illinois River and Upper White River watersheds in the Boston Mountains and Ozark Highlands ecoregion. Information from U.S. eological Survey (US S), Environmental Systems Research Institute (ESRI) and National Aeronautics and Space Administration (NASA). Table . Percent of forest, pasture and urban land use in the Big Creek, Buffalo River, Upper Illinois and Upper White River watersheds. Watershed Forest Pasture Urban - - - - - - - - - - - - - - - - - - - - - % - - - - - - - - - - - - - - - - - - - - - Big Creek* Upstream 89 5 8 0 2 6 Downstream 79 5 17 0 3 5 Buffalo River 52 - 99 0 - 25 0 - 1 Upper White River 34 - 90 7 - 55 0 - 44 Upper Illinois River 2 - 70 27 - 69 3 - 61 *Up and downstream of CAFO operation and fields permitted to receive manure The relationship between land use and stream utting Stream Nutrient nutrient concentrations is not a model that can be used to predict concentration. Given the large vari- Concentrations Into Context at ability observed in these relationships, they simply Big Creek show trends between two variables, land use and [B] Geometric mean concentrations of stream P and stream nutrient concentrations. Continued monitor- N are related to the percent of watershed drainage ing of stream concentrations in Big Creek will area in pasture and urban land use for the Buffalo, continue to more reliably define trends. Upper Illinois and Upper White River watersheds (R2 of .56 to .81 where the number of observations is 71; As the percent pasture and urban land (i.e., land Figure 2)[C]. The dashed lines on Figure 2 represent use intensity) increases, so does stream P and N con- the upper and lower thresholds concentrations, where centrations (see Figure 2). The general increase in there is a 95 percent confidence that a stream draining nutrient concentrations is consistent with the fact that a watershed with a specific percent pasture and urban fertilizer (as mineral and manure sources) is routinely land use will have a P and N concentration within applied to pastures to maintain forage production, as those thresholds. well as deposition of nutrients by grazing cattle. Wate rsheds 0 Beaver Reservoir Water shed • Buffalo River Wate rshed ti Illi nois River Wate rshed 0.20 8 Nitrate-N I Dissolved P , I .t{ 0.16 y = O.OO8e0.022x , y = O.O92e0.043x I .--< , , 6 I .'.....i 2 ,. R2 = 0.78 R = 0.5 6 ,. ,. I 0.0 0.12 ,. ,. I ,. ,. I E ,. 4 I t:t,, I C ,,, 0.08 l:,. l:,. ,,, 0 ,,, l:,. .f--1 l:,. ro l:,. .,,"'O 0 I.... 2 .,,.,, .f--1 0.04 ... C ... ... Q) -- u C 0.00 0 0 u 0.20 8 , C Total P , Total N ro , , l:,. Q) 0.16 y = O.O13e0.020x , y = O.21Oe0.033x E , , 6 , 2 ,. 2 u R = 0.6 1 , R = 0.82 , ,. , , I.... 0.12 ,.'"!:,. , .f--1 , , Q) ,. ,. , l:,. ,, 1:1:. E 4 0 0.08 l:,. Q) 0 l:,. l9 l:,. l:,. 2 0.04 l:,. l:,. l:,. ... l:,. ... l:,. ,; _ - - - zr -- ---- ------- -- 0.00 --- -- 0 0 20 40 60 80 100 0 20 40 60 80 100 Percent of land in pastur e and urba n use, % - Figure 2. Relationship between land use and the geometric mean N and P concentrations (mg L ) in the Buffalo, Upper Illinois and Upper White River watersheds. Dashed lines represent the 95 percent confidence intervals for the estimated mean (solid line). Green points are geometric mean concentrations measured upstream of the CAFO on Big Creek and red points are geometric mean concentrations measured downstream of the CAFO on Big Creek. ____________________ [B]“Geometri means” – There are many ways to calculate the central or typical value of a data set, like the average or median. With water quality data, the geometric mean is often used because it minimizes the influence of really low or high values on the average. [C]“R2” is the oeffi ient of determination – the proportion of variance in the dependent variable (i.e., vertical axis) that is predictable from the independent variable (i.e., horizontal axis). The closer to 1 the value is, means less variability and the better the relationship between the two variables is. In the Big Creek watershed, the percent of land influenced by human activities (i.e., pasture plus Have Nutrient Concentrations urban) doubles from ~1 percent to ~2 percent in Changed in the Short Term at the drainage area upstream and downstream of the CAFO. In Big Creek itself, upstream of the swine Big Creek? Long-term (e.g., decadal scale) water quality data production CAFO, the geometric mean concentrations of dissolved P, total P, nitrate-N and total N during are needed to reliably assess how stream nutrient 1 concentrations have changed in response to water- base flow were .