Increased urbanization in the United States and the rest of the world, has led to more research on the effects it has on the local ecology. Urbanization can be defined as the creation of impervious cover in areas previously covered by natural vegetation (forest, grassland or farmland) as well as the potential influence of sewage treatment plants. Small increases in impervious cover can cause noticeable changes in stream chemistry. The goal of this study is to quantify the impact of smaller industrial cities on water and sediment geochemistry in a largely agricultural watershed. The study area is in east-central Indiana along the west fork of the White River and includes the cities of Winchester, Muncie and Anderson. This area is dominated by agriculture and the impact of cities in the region on water chemistry has not been studied. To evaluate this impact, sampling sites were selected up- and downstream of the three cities to characterize White River water chemistry before and after it flows through the cities as well as sewage treatment plants. Sampling was done over the course of one year to obtain samples characteristic of high and low flow river conditions. Samples were analyzed for major cation and anion concentrations as well as total suspended solids. Metals data was also obtained in sediments, although sampled only twice throughout the study. Results show that sediment load, on average, increases on the downstream side as the river flows through urbanized areas. Chemical analyses show that major cations and anions, Na, K, SO4 and Cl, have distinct spikes in concentration on the downstream side of the cities, as well. Na and Cl are specifically linked to human and urbanized activity, and were up to four times higher downstream of urbanized cities. The concentration of other major ions, including Ca, Mg and NO3, was mostly due to agricultural land use and local bedrock geology. Trace metals characteristic of pollution from automobiles, including Cd, Cr and Zn, showed large increases downstream of urban areas as well. This indicates that even in an area that is largely dominated by agriculture, smaller cities have a quantifiable impact to White River water quality. / Department of Geology

Indiana University-Purdue University Indianapolis (IUPUI) / An investigation of mercury (Hg) in soils and stream sediments was conducted to understand the impact of urbanization on Hg deposition and accumulation on the upper west fork of the White River watershed in central Indiana. Samples were collected to the north and east (i.e., downwind) of emission sources to understand the anthropogenic influences on Hg distribution in soil. Stream sediment sampling was designed to characterize the riverine particulate deposition of Hg through Indianapolis and to predict the potential for stream sediments with high Hg to become sources of methylmercury (MeHg). Spatial analysis revealed that soil Hg was elevated downwind of known industrial emission sites, indicating a local footprint of Hg deposition in central Indiana. Hg in streambank sediments was generally low in up-river sites to the northeast of Indianapolis, and increased markedly as the White River flowed through downtown, with high Hg persisting to downstream rural locations far to the south approximately 40 miles. The stream sediment results also revealed variations in total Hg (Hg(T)) as a function of local depositional sources, sub-watershed location, combined sewer outflows (CSOs), and impoundments along the White River. Low Hg values were recorded where the White River flow rate increased south of the 16th street dam at the confluence of the Fall Creek, where bankside industry and development confine the river. Three tributaries feeding into the White River were included in this study site, all having CSOs. Fall Creek and Pleasant Run have higher values of Hg with Lick Creek having lower values in comparison to the White River and other tributaries. The highest values occur right before confluences to the White River where the flow rate slows and drops sediment. Mercury values typically increased immediately downstream of dams and impoundments. Hg(T) deposition and transport processes pose a problem to anglers fishing south of Indianapolis who may not be aware of the potential dangers related to elevated stream sediment Hg values and the greater potential for MeHg production from these sediments.

Indiana University-Purdue University Indianapolis (IUPUI) / The transport of excess nutrients, sediment, and other contaminants to surface waters has been shown to cause a number of environmental and human health concerns. An understanding of the export pathways that these contaminants follow to surrounding water bodies is crucial to the anticipation and management of peak concentration events. Several studies have demonstrated that the majority of annual contaminant loading in the Midwest occurs during periods of elevated discharge. However, many studies use a limited number of sampling points to determine concentration patterns, loadings, and fluxes which decreases accuracy. Through high-resolution storm sampling conducted in a 2945 km2 (1137 mi2) area of central Indiana’s Upper White River Watershed, this research has documented the complex concentration signals and fluxes associated with a suite of cations, nutrients, and contaminants and isolated their primary transport pathways. Additionally, by comparing the results of similar studies conducted on smaller areas within this watershed, differences in concentration patterns and fluxes, as they relate to drainage area, have also been documented. Similar to the results of previous studies, NO3- concentrations lacked a well-defined relationship relative to discharge and was attributed to primarily subsurface contribution. DOC was exported along a shallow, lateral subsurface pathway, TP and TSS via overland flow, and TKN through a combination of both. Near or in-channel scouring of sediment increased DOC, TKN, TP, and TSS concentrations during Storm 2. Atrazine export was attributed to a combination of overland and subsurface pathways. 2-MIB and geosmin derived from different sources and pathways despite being produced by similar organisms. 2-MIB concentration patterns were characterized by dilution of an in-stream source during Storm 1 and potential sediment export during Storm 2 while in-stream concentrations or a sediment source of geosmin was rapidly exhausted during Storm 1. Many of the concentration patterns were subject to an exaggerated averaging effect due to the mixing of several larger watersheds, especially during Storm 1. This research illustrates the need for high-frequency sampling to accurately quantify contaminant loads for total maximum daily load (TMDL) values, developing best management practices (BMPs), and confronting the challenges associated with modeling increasingly larger-scale watersheds.

Indiana University-Purdue University Indianapolis (IUPUI) / This study explores relationships between temperate stream geochemistry and watershed land cover in two temperate streams, Fishback Creek and School Branch Creek, located in a rapidly urbanizing area on the northwest side of Indianapolis in Eagle Creek Watershed, Indiana. The temporal and spatial patterns of NO3-N, PO4, DOC, SiO2, Cl-, and Na+ were assessed to understand the influence of land cover on the magnitude and timing of water, chemical, and nutrient delivery to streams. Results of the study indicate that the influences of different land cover types on water delivery to streams and in-stream water quality vary seasonally and with respect to flow regime, that urbanization may result in decreased nitrate input, and that phosphate and dissolved organic carbon concentrations will likely remain constant as the watershed is developed. Results also indicate that riparian buffer downstream of intense agriculture lands dilutes high agricultural NO3-N concentrations, but not enough to return in-stream concentrations to natural levels.

Indiana University-Purdue University Indianapolis (IUPUI) / Numerous studies have investigated the fate of pollutants in riparian buffers, but few studies have focused on the control of multiple contaminants simultaneously in riparian zones. To better understand what drives the biogeochemical cycles of multiple contaminants in riparian zones, a 19-month study was conducted in riparian buffers across a range of hydrogeomorphic (HGM) settings in the White River watershed in Indiana. Three research sites [Leary Webber Ditch (LWD), Scott Starling (SS) and White River (WR)] with contrasting hydro-geomorphology were selected. We monitored groundwater table depth, oxidation reduction potential (ORP), dissolved oxygen (DO), dissolved organic carbon (DOC), NO3-, NH4+, soluble reactive phosphorus (SRP), SO42- , total Hg and methylmercury (MeHg). Our results revealed that differences in HGM conditions translated into distinctive site hydrology, but significant differences in site hydrology did not lead to different biogeochemical conditions. Nitrate reduction and sulfate re-oxidation were likely associated with major hydrological events, while sulfate reduction, ammonia and methylmercury production were likely associated with seasonal changes in biogeochemical conditions. Results also suggest that the LWD site was a small sink for nitrate but a source for sulfate and MeHg, the SS site was a small sink for MeHg but had little effect on NO3-, SO42- and SRP, and the WR was an intermediate to a large sink for nitrate, an intermediate sink for SRP, and a small source for MeHg. Land use and point source appears to have played an important role in regulating solute concentrations (NO3-, SRP and THg). Thermodynamic theories probably oversimplify the complex patterns of solute dynamics which, at the sites monitored in the present study, were more strongly impacted by HGM settings, land use, and proximity to a point source.

Indiana University-Purdue University Indianapolis (IUPUI) / The characterization of the nutrients nitrogen, phosphorus and carbon (NPC) export to streams during storms is an integral part of understanding processes affecting water quality. Despite the fact that excessive levels of these nutrients in the Mississippi River basin adversely affects water quality in the Gulf of Mexico, little research has been conducted on NPC dynamics during storms on larger (>20 km2) agriculturally dominated Midwestern watersheds. This project examined the storm export of nitrate, ammonium, total phosphorus, and dissolved organic carbon (DOC) in the upper Eagle Creek Watershed (UECW) (274 km2) in Central Indiana, USA. Water samples were collected during five winter and spring storms in 2007 and 2008 on the rising and falling limb of the hydrograph, in order to characterize NPC dynamics during storm events. Stream discharge and precipitation was monitored continuously, and major cations were used to examine changes in source water over the duration of the storm and assist in the determination of potential flowpaths. DOC, total P, and TKN (Total Kjeldahl Nitrogen) tended to peak with discharge, while nitrate usually exhibited a slight lag and peaked on the receding limb. Total phosphorus, NH3-, TKN, and DOC appear to be delivered to the stream primarily by overland flow. NO3--N appear to be delivered by a combination of tile drain and macropore flow. Overall UECW displayed smoother nutrient export patterns than smaller previously studied watersheds in the area suggesting that scale may influence nutrient export dynamics. Further research is underway on a 3000 km2 watershed in the area to further examine the role scale may play in nutrient export patterns.