Arkansas Bulletin of Water Research - Issue 2018

The Arkansas Bulletin of Water Research is a publication of the Arkansas Water Resources Center (AWRC). This bulletin is produced in an effort to share water research relevant to Arkansas water stakeholders in an easily searchable and aesthetically engaging way. This is the second publication of the bulletin and will be published annually. The submission of a paper to this bulletin is appropriate for topics at all related to water resources, by anyone conducting water research or investigations. This includes but is not limited to university researchers, consulting firms, watershed groups, and other agencies. Prospective authors should read the “Introduction to the Arkanasas Bulletin of Water Research” contained within this publication and should refer to the AWRC website for additional infromation. https://arkansas-water-center.uark.edu

Constituent Loads and Trends in the Upper Illinois River Watershed and Upper White River Basin: 2015 October through 2018 September

The Arkansas Natural Resources Commission (ANRC) identified two priority hydrologic unit code (HUC) 8 watersheds, the Upper White River Basin (UWRB; HUC 11010001) and the Upper Illinois River Watershed (UIRW; 11110103), in northwest Arkansas. Nonpoint source (NPS) pollution is a concern in these watersheds, such as excess nutrients from agriculture and sediment from changes in land uses. Several NPS pollution projects have been funded by ANRC, including streambank restoration on Sager Creek and best management practices (BMP) to control urban sediment in Fayetteville. The purpose of this project was to collect water samples at 15 sites in the UWRB and UIRW to estimate constituent loads and understand how water quality has been changing in these priority watersheds over time

Constituent Loads and Trends in the Upper Illinois River Watershed and Upper White River Basin

Water chemistry can greatly influence the quality of surface waters and affect the ability for streams and rivers to meet their designated use(s). In Arkansas, many streams and rivers were placed on the 2008 303(d) list of impaired water bodies due to excess levels of nutrients, chlorides, sulfates, and sediments (ADEQ, 2008). These constituents continue to be listed as the potential cause for water‐quality impairments through the most recent draft 303(d) list (ADEQ, 2014). The Arkansas Non‐Point Source (NPS) Management Program wants to reduce poll‐ utant loading from the landscape and improve water quality, where funding for projects is targeted to priority watersheds throughout the State

Constituent Load Estimation in the Lower Ouachita-Smackover Watershed

Water quality was monitored at 21 sites in the Lower Ouachita‐Smackover Watershed from 2013 November through 2014 September. The U.S. Geological Survey maintains discharge monitoring stations at two of these sites, Moro Creek (USGS 07362500) and Smackover Creek (USGS 07362100), which were sampled during base flow and storm event conditions, whereas the other sites were only sampled during baseflow. The Arkansas Water Resources Center (AWRC) estimated constituent loads for nitrate‐N (NO₃‐–N), total nitrogen (TN), soluble reactive phosphorus (SRP), total phosphorus (TP) and total suspended solids (TSS) using the U.S. Geological Survey LOADEST software. LOADEST creates regression models between constituent concentrations and discharge, as well as time. The resulting models were applied to daily discharge throughout calendar years 2013 and 2014 to estimate loads. Annual and monthly loads and flow volumes for each site are summarized in this report

Litter Conditioning is Differentially Affected by Leaf Species, Phosphorus Enrichment, and Light Availability

Anthropogenic enrichment of nitrogen and phosphorus is one of the most pervasive and detrimental threats to aquatic ecosystems worldwide. In streams that rely on allochthonous basal food resources, such as leaves, nutrient pollution can result in altered food quality and decreased carbon (C) standing stocks. However, the magnitude and mechanisms of this change in quality are poorly understood. Laboratory microcosm studies were conducted to 1) quantify the response of litter C:P to a gradient of phosphorus (P) enrichment (0, 0.05, and 0.5 mg SRP/L) across leaf species with variable levels of degradability (sugar maple and oak), and 2) quantify the response of litter C:P to a range of P concentrations (0, 0.05, and 0.5 mg SRP/L) and light availability (15 and 500 µmol photons m-2 s-1). Results of the first experiment showed that litter %P increased and C:P decreased with increasing water column P concentrations and this response was greater for the more labile maple species. Carbon:P remained relatively constant through time in the low-P treatments (2600 for both maple and oak) and declined significantly in the high-P treatments (480 and 1040 for maple and oak, respectively). Results of the second experiment demonstrated that phosphorus concentrations and light availability differentially affected algal biomass (as chlorophyll a), microbial metabolic rates, and litter stoichiometry. Algal biomass responded to increased P enrichment only when coupled with greater light intensity, and respiration rates increased with P enrichment in both light levels. Litter C:P ratios decreased significantly with P enrichment with a differential response across light intensities. Our results demonstrate the complexities of nutrient pollution on forested stream ecosystem functioning where allochthonous food resources are important. The effects of nutrient enrichment on detrital quality can provide an important link to understanding how nutrient loading impacts aquatic consumers and potential biodiversity losses

Dissolved Oxygen Monitoring in Kings River and Leatherwood Creek

The Clean Water Act (CWA) establishes the basic structure used to regulate water quality. Under the CWA, States are required to assess water bodies relative to water‐quality standards and designated beneficial uses and then to submit lists of impaired bodies every other year to the US Environmental Protection Agency (USEPA). In 2015, at least 4,800 water bodies were listed as impaired by dissolved oxygen across the US (USEPA, 2015). Aquatic species like fish and macroinvertebrates depend on adequate dissolved oxygen for survival. Low dissolved oxygen can lead to fish kills, reduced aquatic diversity, and nuisance smells from anaerobic conditions – ultimately, low dissolved oxygen concentrations result in water bodies not being able to meet the aquatic life designated use

The potential release of phosphorus in floodplains

In the Illinois River Watershed, there has been growing concern over elevated phosphorus concentrations in the water column. This study evaluated how much phosphorus is contributed from floodplain soils into surface waters, examining the relationship between the flux of phosphorus released and the amount of phosphorus stored in the soil. This was investigated by artificially inundating soil cores from four sites and determining the soluble reactive phosphorus concentrations of the overlying water and the levels of Water and Mehlich-3 extractable phosphorus in the soil. The flux of phosphorus to the overlying water ranged from 0.43 to 6.61 mg m-2 hr-1 within the short-term (16.5-hr incubation) and 0.06 to 1.26 mg m-2 hr-1 over the long term (282.5-hr incubation). Phosphorus flux to the overlying water was significantly correlated with the amount of phosphorus stored in the soil. This study showed that riparian soils with elevated phosphorus content have the potential to release phosphorus when flooded

Arkansas Bulletin of Water Research - Inaugural Issue 2017

The Arkansas Bulletin of Water Research is a publication of the Arkansas Water Resources Center (AWRC). This bulletin is produced in an effort to share water research relevant to Arkansas water stakeholders in an easily searchable and aesthetically engaging way. This is the inaugural publication of the bulletin and will be published annually. The submission of a paper to this bulletin is appropriate for topics at all related to water resources, by anyone conducting water research or investigations. This includes but is not limited to university reserachers, consulting firms, watershed groups, and other agencies. Prospective authors should read the “Introduction to the Arkanasas Bulletin of Water Research” contained within this publication and should refer to the AWRC website for additional infromation. https://arkansas-water-center.uark.edu

Turbidity and Ion Concentrations Vary with Land Use and Underlying Geology at the West Fork of the White River

The West Fork of the White River (WFWR) watershed in northwest Arkansas is a trans-ecoregion watershed and is experiencing land-use changes, especially in the downstream portion of the watershed. The entire 54-km long river has been on the State’s 303(d) list of impaired waterbodies for turbidity, total dissolved solids (TDS), and sulfate for many years. The purpose of this study was to identify which part(s) of the river fail to meet applicable water quality standards (WQS) and to investigate possible sources of pollutants, whether human-caused or naturally occurring. Water samples were collected once or twice a month at 9 sites along the WFWR from June 2014 through June 2018 and analyzed for turbidity, TDS, sulfate, and chloride. Median turbidity values ranged from 1.8 to 10.8 NTU and generally increased from upstream to downstream (