Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 119

Full-Text Articles in Fresh Water Studies

Tree-Ring Reconstruction Of Ouachita River Streamflow, Keaton Cade Jenkins-Joyce Dec 2023

Tree-Ring Reconstruction Of Ouachita River Streamflow, Keaton Cade Jenkins-Joyce

Graduate Theses and Dissertations

The Ouachita River drains the Ouachita Mountains and Upper Coastal Plain in Arkansas and Louisiana. The Ouachita River is used for navigation, power generation, recreation, water supply, and wastewater treatment. The river has been prone to low flows during drought and extreme flooding, which were principal justifications for the construction of three large multipurpose dams on the stream. It is likely that the use of the Ouachita River will be stressed by future population growth, economic expansion, and climate change. For this study, tree-ring chronologies from various locations in and near the Ouachita River drainage basin were used to reconstruct …


Evaluation Of Hydrogeochemical Characteristics Of San Joaquin, Tulare, And Mojave Aquifers, Southern California, Maedeh Hassanvand May 2023

Evaluation Of Hydrogeochemical Characteristics Of San Joaquin, Tulare, And Mojave Aquifers, Southern California, Maedeh Hassanvand

Graduate Theses and Dissertations

Before making attempts to enhance and manage the quality of water, a thorough understanding of these processes is necessary since the chemical quality of groundwater is impacted by a number of linked processes. This would be more important in arid and semiarid regions like the southern part of California where more rely on groundwater for agriculture and drinking water uses than the other states. As a result, fundamental knowledge of the governing processes of groundwater chemistry is required for effective water resource management. Thus, this study is primarily concerned with three aspects in Mojave, Tulare, and San Joaquin aquifers: The …


Arkansas Bulletin Of Water Research - Issue 2021-2022, Erin Grantz, Lillie Haddock, Brian E. Haggard Jan 2022

Arkansas Bulletin Of Water Research - Issue 2021-2022, Erin Grantz, Lillie Haddock, Brian E. Haggard

Arkansas Bulletin of Water Research

The Arkansas Bulletin of Water Research (Bulletin) is a publication of the Arkansas Water Resources Center (AWRC). We publish the Bulletin to communicate the major findings of research funded by the Water Resources Research Act Section 104(b) in Arkansas. This research is relevant to Arkansas water stakeholders, and the Bulletin provides an easily searchable and aesthetically engaging access option.

This is the fourth publication of the Bulletin. This issue contains final reports from research projects that were funded by the 104(b) program in fiscal years 2019 and 2020. The articles in this issue can be cited as an AWRC publication. …


Nutrient Uptake And Management Strategies In Recirculating Hydroponic Systems, Lauren Leigh Houston Dec 2021

Nutrient Uptake And Management Strategies In Recirculating Hydroponic Systems, Lauren Leigh Houston

Graduate Theses and Dissertations

Nutrient management in recirculating hydroponic systems requires the periodic replenishment of water and nutrients to the nutrient solution reservoir. Common nutrient management strategies, such as replenishing the reservoir with fresh solution and maintaining a constant solution electrical conductivity (EC), can lead to ion accumulation and nutrient imbalances since nutrients are taken up by roots and depleted from solution at different rates. To avoid nutritional disorders, commercial growers typically dump and replace the hydroponic solution periodically, which is wasteful and has an economic cost. A potential alternative is to specially formulate the nutrient replenishment solution to balance the supply of nutrients …


Characterization Of Problematic Red Clay Soils In Arkansas For The Purpose Of Onsite Wastewater System Placement, Bailey Darnell May 2021

Characterization Of Problematic Red Clay Soils In Arkansas For The Purpose Of Onsite Wastewater System Placement, Bailey Darnell

Graduate Theses and Dissertations

Distinguishing between red-clay soils that are non-expansive and can reduce and red-clay soils developing in problematic red parent material, which are expansive, but also non-reducing, is key for proper on-site wastewater system placement. The Arkansas Department of Health allows for the placement of on-site wastewater systems in certain red-clay soils that have the potential to reduce, but only in the Ozark Highlands [Major Land Resource Area (MLRA) 116A], which is referred to as the red-soil exception. There is currently little scientific data to support the geographic restriction of the red-soil exception. The objectives of this study were to: i) confirm …


Projected Surface Water For Fruit And Vegetable Irrigation Under A Changing Climate In The Us, Marty Matlock, Greg Thoma, Kieu Ngoc Le, Eric Cummings, Zach Morgan, Andrew Shaw Jun 2020

Projected Surface Water For Fruit And Vegetable Irrigation Under A Changing Climate In The Us, Marty Matlock, Greg Thoma, Kieu Ngoc Le, Eric Cummings, Zach Morgan, Andrew Shaw

Water Systems

Increasing greenhouse gas concentrations in the atmosphere, resulting in climate impacts, are raising concerns over the hydrologic cycle and its effects upon agricultural productivity. If rainfall patterns change, meeting an increased demand for fruits and vegetables will pose a challenge for domestic production regions in the United States (U.S.). Information on potential water supply scarcity in the current production regions provides decision makers with critical information for risk mitigation for future production. We used a hydrologic balance-based model of historic and future water availability to evaluate risk of available irrigation water to support major fruit and vegetable production the US. …


Reduced Disposal Area Performance Utilizing Secondary-Treated Effluent In Profile-Limiting Soils, David A. Meints May 2019

Reduced Disposal Area Performance Utilizing Secondary-Treated Effluent In Profile-Limiting Soils, David A. Meints

Graduate Theses and Dissertations

Onsite wastewater systems dispose of primary treated effluent by utilizing the soil for final recycling and renovation of wastewater into the environment. Soil and site limitations have become a challenge to design a wastewater system and dispose of onsite wastewater using a conventional pipe and gravel design. Using secondary-treated effluent from an advanced treatment unit applied to a reduced disposal area offers an additional alternative when developing an onsite wastewater system. The objective of this study was to determine the feasibility of hydraulically loading limiting soils with secondary-treated effluent in a reduced disposal area. A reduced disposal area was constructed …


The Potential Acidification Of The Mulberry River, Arkansas, Jason Richard Burgess-Conforti May 2019

The Potential Acidification Of The Mulberry River, Arkansas, Jason Richard Burgess-Conforti

Graduate Theses and Dissertations

The Mulberry River is a 110 km long tributary of the Arkansas River in northwest Arkansas and has been designated as a National Wild and Scenic River since 1992. In 2008, the Mulberry River was added to the 303(d) list of impaired water bodies due to the low pH of a 14.6 km segment of the river which has since increased to 68.7 km. To date, there has been little research performed on the Mulberry River and long-term routinely sampled water quality data is unavailable. The objectives of this dissertation were 1) to evaluate changes in water quality of the …


Landuse And Soil Property Effects On Infiltration And Soil Aggregate Stability In The Lower Mississippi River Valley, Rebecca Lynn Anderson May 2019

Landuse And Soil Property Effects On Infiltration And Soil Aggregate Stability In The Lower Mississippi River Valley, Rebecca Lynn Anderson

Graduate Theses and Dissertations

Following European settlement of the Lower Mississippi River Valley (LMRV), agricultural expansion and unsustainable, agriculturally related practices have caused groundwater depletion, soil erosion, and surface water contamination by eroded sediments and sediment-bound nutrients to become major environmental threats to the region. The objective of this study was to evaluate the effects of common landuses [i.e., native prairie, deciduous forest, coniferous forest, Conservation Reserve Program (CRP) grassland, and conventional-tillage (CT) and no-tillage (NT) agriculture] on surface water infiltration and aggregate-stability-related properties [i.e., water-stable macroaggregate (WSA) size distribution, total water-stable macroaggregate (TWSA) concentration, and mean weight diameter (MWD)]. The overall infiltration rate …


Incorporating Recent Geochemical And Isotopic Constraints In Age Dating The Waters Of Hot Springs National Park, Arkansas, Kristina Marie Raley May 2019

Incorporating Recent Geochemical And Isotopic Constraints In Age Dating The Waters Of Hot Springs National Park, Arkansas, Kristina Marie Raley

Graduate Theses and Dissertations

Mean water age for spring discharge in Hot Springs National Park was calculated as approximately 4,400 years by Bedinger et al (1978) using carbon-14. Their analysis indicated that the water was a mixture of a small portion of cold water that was less than twenty years old with a preponderance of hot water. However, this result includes some error due to Bedinger et al. using general isotopic values for soil dissolved inorganic carbon and mineral carbon instead of obtaining actual values from the study area. A more accurate age calculation for the springs has been made possible by additional geological …


Margaret White Springs Recharge Study, Buffalo National River, North-Central Arkansas, Usa, Ashlon Elizabeth Leonard Dec 2018

Margaret White Springs Recharge Study, Buffalo National River, North-Central Arkansas, Usa, Ashlon Elizabeth Leonard

Graduate Theses and Dissertations

Margaret White Springs (MWS) is one of the largest springs in the middle section of the Buffalo National River (BNR) and contributes several tens of cubic feet per second of flow to river discharge on average, yet the source of the water has not been fully studied or documented. The spring is located approximately 4 miles downstream from Robertson Hole, a losing reach of the river. At Robertson Hole the river loses a significant amount of flow to groundwater, which during the dry season (summer) can be as much as 100%. Flow in the main channel is re-established at MWS; …


Estimating Watershed Mercury Contribution To Lake Fort Smith State Park, Arkansas, Usa, William Miles Harmon Aug 2018

Estimating Watershed Mercury Contribution To Lake Fort Smith State Park, Arkansas, Usa, William Miles Harmon

Graduate Theses and Dissertations

Mercury contamination associated with human activities poses global human health and environmental risks. A fish-consumption advisory has been in effect at Lake Fort Smith in central west Arkansas for more than a decade due to observed methylmercury concentrations in fish tissue. Lake Fort Smith is an important municipal drinking water supply and recreational resource. Water samples from the majority contributing tributary stream, Frog Bayou creek, were collected periodically, under differing hydrologic conditions in order to quantify the allochthonous mercury load delivered to the lake. Temperature, specific conductance, and turbidity data were collected and used to estimate dissolved organic carbon, methylmercury …


Applications Of Reservoir Limnology Theory And Steady-State Modeling To Eutrophication Management In Beaver Lake, Arkansas, Matthew Rich May 2018

Applications Of Reservoir Limnology Theory And Steady-State Modeling To Eutrophication Management In Beaver Lake, Arkansas, Matthew Rich

Graduate Theses and Dissertations

Reservoir limnology theory predicts that phytoplankton biomass (PB) is greatest in riverine-transition zones and least in lacustrine zones leading to an inverse pattern in water clarity. These theoretical patterns were utilized to create a statistical model of chlorophyll-a (Chl-a), an indicator of PB, and Secchi transparency (ST), an indicator of Chl-a, in Beaver Lake, Arkansas, a 12,800-ha reservoir, in order to hindcast historical conditions. Sampling for Chl-a, ST, and photic depth occurred semimonthly at 12 locations along a 78-km transect from the river inflow to the dam during the 2015 growing season. The ratio of Chl-a and ST measured at …


Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise Aug 2016

Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise

Graduate Theses and Dissertations

A steady-state mass diffusion model used with simple measurable and calculable inputs for determining sediment oxygen demand (SOD) is compared to an intact core incubation (ICI) SOD method using samples from three lakes. The mass diffusion model coupled with inputs is known as the measure-calculate method (M-C) and is a potential alternative to existing methods for measuring SOD which are more complex, time-consuming, and costly. The M-C method requires inputs for volumetric sediment oxygen uptake (Ṅsed), sediment density and porosity, and water properties. Ṅsed was determined by suspending sediment in oxygen-saturated water with a DO probe and determining the steady …


Optical Water Quality And Human Perceptions Of Rivers, Amie West Aug 2016

Optical Water Quality And Human Perceptions Of Rivers, Amie West

Graduate Theses and Dissertations

Understanding water quality dynamics in recreational rivers is integral in shaping management strategies that maintain ecosystem health, perceived value and appeal, and regional economic significance in a changing environment. Optical water quality describes the behavior of light in water as governed by its physical and chemical composition, and is among the strongest influences on human perceptions of water quality. Ethnohydrology is the study of culturally constructed knowledge and understanding of water. This work is the culmination of an interdisciplinary approach to water resources research—integrating optical water quality and ethnohydrology methods to recognize the intersection between measured water quality and visible …


Chlorine Demand Shows Thresholds And Hierarchy With Source Water Quality At Beaver Lake, Arkansas, Jaime M. Gile Aug 2016

Chlorine Demand Shows Thresholds And Hierarchy With Source Water Quality At Beaver Lake, Arkansas, Jaime M. Gile

Graduate Theses and Dissertations

This study investigated the effects of source water quality in Beaver Lake on the amount of chlorine (Cl) needed to develop decision support system to help guide chlorination practices in pre-treatment of source water. Chlorine demand assays were performed on water samples from Beaver Lake collected from the intake structure at Beaver Water District from March 2014 through August 2015, and using data from these assays, the two points of interest in this study were the Cl dose at which Cl residuals began to accumulate and the mean Cl demand occurring after that dose. Three methods of analysis were used …


Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson May 2016

Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson

Graduate Theses and Dissertations

A widespread stressor, anthropogenic nitrogen (N) and phosphorus (P) pollution can increase resource nutrient content and alter animal community composition in freshwater ecosystems. In this dissertation, I used ecological stoichiometry theory to examine effects of diet nutrient content and leaf litter type on growth, regulation, and wastes of aquatic invertebrate detritivores. I tested effects of leaf litter diet carbon:phosphorus (C:P) on growth and stoichiometric regulation of the detritivorous caddisfly Pycnopsyche lepida and used results to determine a threshold elemental ratio of oak litter C:P=1620 that confers peak growth of this species. This empirical, growth-based approach provided a more accurate estimate …


Hydrology-Biology Response Relationships In The Ozark Highlands, Dustin Thomas Lynch Dec 2015

Hydrology-Biology Response Relationships In The Ozark Highlands, Dustin Thomas Lynch

Graduate Theses and Dissertations

I examined flow-ecology relationships among stream communities in the Ozark Highlands, USA. I sampled fish, crayfish, and benthic macroinvertebrates during two consecutive summers, including a drought year (2012) and a flood year (2013). Biological response variables related to community structure were assessed via two different statistical methods: an Information Theoretic approach relating response variables to a priori selected predictor variables incorporating hydrology, habitat, geomorphology, and water quality, and canonical ordination using forward selection to relate these same response variables to a large assortment of hydrologic metrics. In addition to assessing metrics related to predicted natural flow, flow alteration at gaged …


Effects Of Landscape Disturbances On Autotrophic Processes Within Arkansas Ozark Streams, Bradley J. Austin May 2015

Effects Of Landscape Disturbances On Autotrophic Processes Within Arkansas Ozark Streams, Bradley J. Austin

Graduate Theses and Dissertations

Land-use change is one of the most widespread human impacts and can influence abiotic and biotic processes within surrounding streams. For example, streams in agricultural and urban watersheds receive greater light and nutrient inputs that can promote increased algal growth and primary production. Natural gas (NG) infrastructure development, a recent land use change in many regions, may also stimulate forested stream primary production, by reducing forest cover and increasing sediments and nutrient transport. I sampled streams across a NG activity gradient for algal biomass and gross primary production (GPP) to assess potential effects of this emerging land-use type. Algal biomass …


Stable Isotopes As A Tool To Characterize Carbon Cycling And Develop Hydrologic Budgets In Mantled Karst Settings, Katherine Knierim May 2015

Stable Isotopes As A Tool To Characterize Carbon Cycling And Develop Hydrologic Budgets In Mantled Karst Settings, Katherine Knierim

Graduate Theses and Dissertations

Isotopes of water (δ2H/δ18O), carbon dioxide (δ13C-CO2), and dissolved inorganic carbon (δ13C-DIC) were used to explore water quality, trace carbon cycling, and quantify recharge sources through mantled karst and into Blowing Spring Cave (BSC). Of the possible sources of contamination in the BSC recharge area, septic-tank effluent was hypothesized to degrade water quality at the spring outlet of BSC because of the dominance of septic tanks for waste treatment, unsuitable topography and soil for septic-tank absorption fields, increased nitrate and chloride concentrations concomitant with increased urbanization, and increased Escherichia coli with discharge. Carbon cycling between the soil and BSC was …


Habitat Assessment And Ecological Restoration Design For An Unnamed Tributary Of Stone Dam Creek, Conway, Arkansas, Paige E. Boyle, Mary C. Savin, James A. Mccarty, Marty D. Matlock Jan 2015

Habitat Assessment And Ecological Restoration Design For An Unnamed Tributary Of Stone Dam Creek, Conway, Arkansas, Paige E. Boyle, Mary C. Savin, James A. Mccarty, Marty D. Matlock

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Urbanization can lead to increased sedimentation, erosion, pollution, and runoff into streams. The United States Environmental Protection Agency’s (USEPA) Rapid Bioassessment Protocols (RBPs) are sets of guidelines that can be used to assess a habitat’s sedimentology, hydrology, vegetation, and geomorphology to determine impairment. An unnamed tributary of Stone Dam Creek on the University of Central Arkansas (UCA) campus in Conway, Arkansas runs partially underground and through the urbanized UCA campus watershed. The stream was assessed using the USEPA’s RBPs to determine impairment of the stream, and received a RBP score of 71.2 out of 200 compared to 153.5 in a …


Development Of A Hydrologic Model For An Urban Headwater Stream: The Influence Of Pervious Surface Properties On Runoff Dynamics, Dawn A. Farver Dec 2014

Development Of A Hydrologic Model For An Urban Headwater Stream: The Influence Of Pervious Surface Properties On Runoff Dynamics, Dawn A. Farver

Graduate Theses and Dissertations

A hydrologic model was developed for the Mullins Creek (MC) catchment located on the University of Arkansas campus in Fayetteville, Arkansas. The MC catchment is a small, dynamic urban stream system with a range of land use/land cover (LULC), an extensive and well-developed stormwater drainage network, and extensive urbanization (over 90% developed, and almost 50% impervious surface area (ISA)). Selected datasets provided information on the stormwater drainage network, the physical attributes of the catchment and receiving waterway (i.e. drainage area, slope, etc.), infiltration potential of soil map units, LULC, and percent ISA. These datasets were analyzed to provide input parameters …


Are Concentration-Discharge Relations Influenced By Water Sample Collection Methods?, William Welch Dec 2014

Are Concentration-Discharge Relations Influenced By Water Sample Collection Methods?, William Welch

Graduate Theses and Dissertations

Two primary methods of stream water sampling, the U.S. Geologic Survey (USGS) equal-width increment (EWI) and point samples (PS) from vertical centroid of flow (VCF) were compared at three river sites, the White River near Fayetteville, Richland Creek at Goshen, and War Eagle Creek near Hindsville. A little over three years of concentration data, which was paired with corresponding instantaneous discharge values (http://ar.water.usgs.gov/), was gathered separately at each site by the Arkansas Water Resource Center (AWRC) and the United States Geological Survey (USGS). The purpose of this study was to evaluate how concentration is related to discharge when water samples …


A Watershed Scale Evaluation Of Selected Second Generation Biofeedstocks On Water Quality, Gurdeep Singh Dec 2012

A Watershed Scale Evaluation Of Selected Second Generation Biofeedstocks On Water Quality, Gurdeep Singh

Graduate Theses and Dissertations

This study compares a novel simulation approach to the conventional Soil and Water Assessment Tool (SWAT) modeler's approach for targeting biofuel crop production on marginal lands. In conventional SWAT modeling approach, non-spatial definition of hydrological response units (HRUs) results in the simulation of biofuel crops on both marginal and non-marginal land. This study provides an alternative approach in which a marginal-land raster was integrated into the land use and land cover (LULC) raster in such a way that the land uses were divided into marginal and non-marginal components. This modified LULC was used for model setup which resulted in marginal …


Groundwater Quality Assessment From Domestic Water Wells In The Fayetteville Shale Gas Play Area In Central Arkansas, Anna Marie Nottmeier Aug 2012

Groundwater Quality Assessment From Domestic Water Wells In The Fayetteville Shale Gas Play Area In Central Arkansas, Anna Marie Nottmeier

Graduate Theses and Dissertations

This study establishes a spatially distributed domestic water well groundwater quality data set, throughout the Fayetteville Shale Gas Play (FSGP) in central Arkansas. The data set facilitates characterization of the geology and groundwater quality across the study area, benefits residents who may have concerns about the potential impacts on their well water quality, and provides a groundwater quality basis to which complaints can be compared and resolved. The assessment included: research of the study area, site reconnaissance, water sampling and collection, interviews with owners of the property, analytical analysis, Quality Assurance and Quality Control, and groundwater data interpretation.

The study …


Nutrient Dynamics In Stormwater Runoff From Green Roofs With Varying Substrate, John Michael Fohner May 2012

Nutrient Dynamics In Stormwater Runoff From Green Roofs With Varying Substrate, John Michael Fohner

Graduate Theses and Dissertations

One major concern with urban development is the increasing amount of stormwater runoff from large expanses of impervious surfaces. These impervious surfaces reduce the ability of stormwater to infiltrate into the soil and eventually groundwater, which leads to greater amounts of surface runoff. Green technology serves as a viable solution to many of the environmental problems presented by modern development. Fifteen mock, extensive green roofs were built in the fall of 2008 at the Watershed Research and Education Center in Fayetteville, Arkansas. The goals of this project were to (1) measure the amount of stormwater runoff from varying treatments and …


White River Forum Ii: Second Annual Meeting Of The White River Forum, John Havel, Kenneth Steele Nov 2009

White River Forum Ii: Second Annual Meeting Of The White River Forum, John Havel, Kenneth Steele

Technical Reports

This second annual meeting of the White River Forum is proof of widespread interest in the water quality of the Upper White River watershed. The participation of numerous elected officials, state and federal agencies, universities, businesses, and local citizens indicates that interest in understanding policy issues crosses political boundaries and occupations.


Development Of A Distributed Artificial Neural Network For Hydrologic Modeling, Rebecca Logsdon Jan 2009

Development Of A Distributed Artificial Neural Network For Hydrologic Modeling, Rebecca Logsdon

Inquiry: The University of Arkansas Undergraduate Research Journal

Hydrological models are used to represent the rainfall-runoff and pollutant transport mechanisms within watersheds. Accurate representation of these dynamic and complex natural processes within a watershed is an important step in managing and protecting a watershed Artificial neural network (ANN) models are often used in hydrologic modeling. Typical ANN models are trained to use lumped data. However, watershed characteristics used as inputs in hydrological modeling are spatially and often temporally dynamic. Therefore, a lumped model does not have the ability to represent changes in spatial dynamics of a watershed. Therefore, the purpose of this study was to develop and test …


Evaluation Of Water-Retention Ability Of Eastern Arkansas Prairie And Agricultural Soil, Maria L. Barrenechea, Kristofor R. Brye Jan 2006

Evaluation Of Water-Retention Ability Of Eastern Arkansas Prairie And Agricultural Soil, Maria L. Barrenechea, Kristofor R. Brye

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Agricultural land use affects soil physical properties, such as bulk density, water content, organic matter content, and soil structure; all of which in turn affect ecosystem productivity. The objective of this study was to evaluate the effects of: 1) time since aboveground biomass has been removed by haying (i.e., 0 vs. 23 years), and 2) land use (i.e., undisturbed tallgrass prairie vs. cultivated agriculture) on water-retention characteristics in a silt-loam soil of the Grand Prairie region of eastern Arkansas. Soil samples were collected from the 0- to 10-cm depth and were wetted with varying amounts of distillated water to create …


Estimating Surface Runoff In The Illinois River Basin For The Management Of Nonpoint-Source Phosphorus Loads, Adam T. Mcclymont, Mary C. Savin, Brian E. Haggard Jan 2006

Estimating Surface Runoff In The Illinois River Basin For The Management Of Nonpoint-Source Phosphorus Loads, Adam T. Mcclymont, Mary C. Savin, Brian E. Haggard

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

With the growing concern about elevated phosphorus (P) concentrations in regional lakes, rivers, and streams, it is essential to investigate factors contributing to P transport from the landscape. Phosphorus fluxes from nonpoint sources, particularly land applications of poultry litter and other animal manures, are closely related to the amount and production of surface runoff. Daily stream discharge and the software program, Base Flow Index (BFI), were used to estimate the amount and temporal patterns of surface runoff at different locations within the Illinois River Basin, including selected tributaries in northwest Arkansas and northeast Oklahoma. Daily streamflow data from nine U.S. …