CURRENT PERSPECTIVES IN CONTAMINANT HYDROLOGY AND WATER RESOURCES SUSTAINABILITY Edited by Paul M Bradley Current Perspectives in Contaminant Hydrology and Water Resources Sustainability http://dx.doi.org/10.5772/47884 Edited by Paul M Bradley Contributors Wei-Zu Gu, Paul M Bradley, Prem B Parajuli, Ying Ouyang, Matjaž Glavan, Marina Pintar, Rozalija Cvejić, Matjaž Tratnik, Luc Descroix, Celeste Journey, Karen Beaulieu, Sakaris, Arshad Ashraf, Francis Chapelle, Zulfiqar Ahmad, Julia Barringer, Pamela A Reilly Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2013 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work Any republication, referencing or personal use of the work must explicitly identify the original source Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher No responsibility is accepted for the accuracy of information contained in the published chapters The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book Publishing Process Manager Viktorija Zgela Technical Editor InTech DTP team Cover InTech Design team First published February, 2013 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechopen.com Current Perspectives in Contaminant Hydrology and Water Resources Sustainability, Edited by Paul M Bradley p cm ISBN 978-953-51-1046-0 free online editions of InTech Books and Journals can be found at www.intechopen.com Contents Preface VII Section Contaminant Hydrology: Surface Water Chapter Managing the Effects of Endocrine Disrupting Chemicals in Wastewater-Impacted Streams Paul M Bradley and Dana W Kolpin Chapter Environmental Factors that Influence Cyanobacteria and Geosmin Occurrence in Reservoirs 27 Celeste A Journey, Karen M Beaulieu and Paul M Bradley Chapter Watershed-Scale Hydrological Modeling Methods and Applications 57 Prem B Parajuli and Ying Ouyang Section Contaminant Hydrology: Groundwater 81 Chapter Arsenic in Groundwater: A Summary of Sources and the Biogeochemical and Hydrogeologic Factors Affecting Arsenic Occurrence and Mobility 83 Julia L Barringer and Pamela A Reilly Chapter Occurrence and Mobility of Mercury in Groundwater 117 Julia L Barringer, Zoltan Szabo and Pamela A Reilly Chapter Modeling the Long-Term Fate of Agricultural Nitrate in Groundwater in the San Joaquin Valley, California 151 Francis H Chapelle, Bruce G Campbell, Mark A Widdowson and Mathew K Landon Chapter Groundwater and Contaminant Hydrology 169 Zulfiqar Ahmad, Arshad Ashraf, Gulraiz Akhter and Iftikhar Ahmad VI Contents Section Water Resources Sustainability 197 Chapter Geospatial Analysis of Water Resources for Sustainable Agricultural Water Use in Slovenia 199 Matjaž Glavan, Rozalija Cvejić, Matjaž Tratnik and Marina Pintar Chapter Changing Hydrology of the Himalayan Watershed 221 Arshad Ashraf Chapter 10 Impact of Drought and Land – Use Changes on Surface – Water Quality and Quantity: The Sahelian Paradox 243 Luc Descroix, Ibrahim Bouzou Moussa, Pierre Genthon, Daniel Sighomnou, Gil Mahé, Ibrahim Mamadou, Jean-Pierre Vandervaere, Emmanuèle Gautier, Oumarou Faran Maiga, Jean-Louis Rajot, Moussa Malam Abdou, Nadine Dessay, Aghali Ingatan, Ibrahim Noma, Kadidiatou Souley Yéro, Harouna Karambiri, Rasmus Fensholt, Jean Albergel and Jean-Claude Olivry Chapter 11 A Review of the Effects of Hydrologic Alteration on Fisheries and Biodiversity and the Management and Conservation of Natural Resources in Regulated River Systems 273 Peter C Sakaris Chapter 12 Current Challenges in Experimental Watershed Hydrology 299 Wei-Zu Gu, Jiu-Fu Liu, Jia-Ju Lu and Jay Frentress Preface Limitations on the availabilityof water resourcesareamong the greatest challenges facing modern society, despite the fact that roughly 70% of the earth’s surface is covered by water Human society depends on liquid freshwater resources to meet drinking, sanitation and hy‐ giene, agriculture, and industry needs.Roughly 97% of the earth’s surface and shallow sub‐ surface water is saline and about 2% is frozen in glaciers and polar ice The remaining 1% is liquid freshwater present to some extent as surface waterin lakes and streams but predomi‐ nantlyoccurring as groundwater in subsurface aquifers.Improved management of these lim‐ ited freshwater resources is a global environmental priority Limitations on useable freshwater are driven by water quantity and quality, both of which are inextricably linked with population growth and, consequently, are expected to worsen in the foreseeable future.In 2005,approximately 35% of the world’s population was estimat‐ ed to inhabit areas with chronic water limitations affecting survival and quality of life The estimated world human population in 2005 was 6.5 billion By the end of 2012, the world’s population reached the billion mark and is expected to exceed billion circa 2050.Water quantity concernsreflectthe availability of freshwater relative to current and future use and, thus, increase with population size.Agriculture and industry dominant water quantity needs are estimated to represent more than 90% of current freshwater use Anthropogenic environmental contamination further limits freshwater resources when concentrations ex‐ ceed water quality standards for drinking water and other human health applications Improved resource monitoring and better understanding of the anthropogenic threats to freshwater environments are critical to efficient management of these freshwater resources and ultimately to the survival and quality of life of the global human population.This book helps address the need for improved freshwater resource monitoring and threat assessment by presentingcurrent reviews and case studies focused on the fate and transport of contami‐ nants in the environment and on the sustainability of groundwater and surface-water re‐ sources The book is divided into three sections, which address surface-water contaminant hydrology, groundwater contaminant hydrology and water resources sustainability around the world The first section, “Contaminant Hydrology: Surface Water,” includes threechapters Chapter addresses the risk of environmental endocrine disruption posed by the release of numer‐ ous wastewater and personal care product contaminants throughout the world Chapter is a case studyin South Carolina, USA that illustrates the complex eco-hydrological interac‐ tions that can lead to accumulation of nuisance and toxic cyanobacteria-derived compounds in surface-water impoundments Chapter reviews currently available surface-water hy‐ VIII Preface drology and water quality models and presents case studies of model applications in two basins in Mississippi, USA The second section, “Contaminant Hydrology: Groundwater,” includes four chapters ad‐ dressing the hydrology and modeling of a range of important groundwater contaminants Chapters and 5reviewthe environment controls on the occurrence and mobility of arsenic and mercury, respectively, in groundwater throughout the world Chapter is a case study of the application of a numerical mass balance modeling approach to assess nitrate migra‐ tion and attenuation in a groundwater system in California, USA Similarly, Chapter presents two case studies on the application of three dimensional contaminant transports modeling to assess aquifer vulnerability and the fate of jet fuel and other oil contaminants in groundwater in Pakistan The third section, “Water Resources Sustainability,” includes five chapters, which addressa range of topics on water resource assessment, alteration impacts, and management Chapter describes the use of a generally applicable geospatial approach to assessingwater resources availability and drought risk in Slovenia Chapter describes the use of an integrated water‐ shed model to predict land-use impacts and improve water resource development in the Hi‐ malayan region Chapter 10 provides an overview of the effects of drought and land-use changes on surface-water hydrodynamicsin the Sahelian region of West Africa Chapter 11 reviews the impacts of stream regulation andhydrologic alterations and presents several management approaches Finally, Chapter 12 provides an overview of common practice and historical weaknesses in experimental watershed hydrology and presents a case study of a new field experimental approach in China designed to address some of these limitations Paul M Bradley, Ph.D Research Ecologist/Hydrologist U.S Geological Survey USA Section Contaminant Hydrology: Surface Water 320 Current Perspectives in Contaminant Hydrology and Water Resources Sustainability shed with drainage area of 82.1 km2 (Figure 16b) Rainfall event A produces a runoff hydro‐ graph peak A, some of the constituents of rainfall event A were delayed to emerge during the rainfall event B It is worth noting that the hydrograph produced by rainfall event A does not have the bell shape referred to in the unit hydrograph concept In fact this delayed correspond‐ ency shows the formation of pre-event water (“old” water) during the runoff process It follows that the current ‘one-to-one correspondency’, used to conceptualize rainfall-runoff relationships in applied hydrology, will be associated with large uncertainty Figure 16 The delayed correspondency phenomena “Old” water paradox identified from both surface and subsurface flows Data from the ‘mini CZEB’ watershed, Nandadish, suggest that pre-event water (“old water”) appeared in all runoff components including surface runoff, interflow and groundwater or saturated flow (Figure 17) Figure 17a and Figure 17b refer to the surface runoff dominated type (type S, from above), and subsurface flow dominated type (type SS) respectively The surface runoff and subsurface runoff processes are shown separately with their corresponding proportions of pre-event water For the type S, the pre-event water accounts for 9% and 24% of the total amount of surface runoff and of subsurface flow respectively while for the type SS, it becomes 11%and 89% respectively [58] This reveals that even in a catchment with an average soil depth of 2.46 m, large volumes of pre-event water (“old” water) are stored and released promptly by event input Hydrochemistry distribution paradox This was termed by Kirchner as the “‘variable chemistry of old water’ paradox: although baseflow and stormflow are both composed mostly of ‘old’ water, they often have very different chemical signatures” [31] However, the artificial catchment at Hydrohill shows paradoxically the distribution of hydrochemical compositions in different runoff components, including event rainfall This ‘hydrochemistry distribution paradox’ results largely from: (1) inorganic ions in event rainfall input emerge in all runoff components; (2) a strong similarity between rainfall and surface runoff but less similarity in subsurface components; and (3) the fact that the total amount of ions of event rainfall is sometimes much smaller than the sum of all runoff components [59] Figure 18 shows the processes of Mg2+ and Cl- in event rainfall, surface runoff, interflow and groundwater flow (saturated flow) Current Challenges in Experimental Watershed Hydrology http://dx.doi.org/10.5772/55087 Figure 17 Processes of various runoff components, and that of their pre-event water of Nandadish (a) for S type; (b) for SS type Figure 18 The Mg2+ and Cl- processes in event rainfall and runoff components of Hydrohill Samples were analysed in Atlanta laboratory of USGS by N.E Peters (same hereinafter) 5.4 Does diel signal of hydrochemical constituents emerge linkage among multi–processes? For the better understanding of the links between contaminants and multi-processes, explo‐ ration of diel signals in natural waters may yield “insight into the intricate linkages among hydrological, biological, and geochemical processes [23]” Diel variations of various hydro‐ logical constituents in surface and subsurface runoff responses during rainfall events were monitored in artificial catchments and monoliths with examples as following (Figure 19) Variations of pH The diel variations of pH in SR, IF, and GF of Hydrohill show their own individuations (solid lines in Figure 19a) Diel variation curve of SR to a large extent appears similar to that of rainfall However, pH variation curve of IF is contrary to that of rainfall after 10 a.m., while the GF curve appears as the flattened IF curve The pH variation curve of the interflow of monolith L1 and that of the flow of monolith LS are reasonably similar to that of 321 322 Current Perspectives in Contaminant Hydrology and Water Resources Sustainability IF and GF of Hydrohill respectively (dot dash lines in Figure 19a) This reveals that the variation of pH in interflow and saturated flow is not driven only by rainfall input but also by “the biological processes of photosynthesis and respiration [22, 60].” This is ascribed to the coupling of the three “reactors” mentioned above via their MC and IMC for transformation and exchange (Figure 4) Figure 19 Diel variations of pH, and hydrochemical constituents SO42-, Ca2+ in event rainfall and runoff responses of Hydrohill and monoliths SR, IF, GF- runoff responses from Hydrohill; L1- monolith of 32 m2 serves as an element slope of Hydrohill; LS - saturated monolith of 1m2 serves as solum in reduction environment; EB3- Morning Glory Catchment of 4573 m2 serves as a catchment without saturated zone formed by debris only Variation of ionic species (1) For anion SO42- : the diel variation curves of runoff responses of both Hydrohill and monoliths, with few exceptions, are contrary to that of rainfall Mostly their peak concentrations happened during evening and midnight (Figure 19b) Different from the case of pH, SO42- of SR has a strong inversion with the event rainfall curve at night time (2) For cation Ca2+: the diel curve of rainfall (Fig.19c) shows a small variation after sunrise However, it triggers variations in runoff responses with their peak concentrations at both a.m and before midnight Highest peak happens to LI at afternoon These diel variations in runoff perhaps are metabolism related (3) Nimick et al [60] discussed diel cycles of dissolved trace metal concentration in a Rocky Mountain stream They found that the anionic species “have their highest dissolved concentrations in the late afternoon” while the cationic species “have their highest dissolved concentrations shortly before sunrise”[23,60] Role of soil Variations of pH, SO42-, Ca2+ in total runoff of Morning Glory Catchment, a special designed catchment without soil but debris (EB3 in Figure 19 with broken lines), are very similar to that of rainfall curves after 20:00 (EB3 data are not enough before this time) The role of soil in the formation of ionic species in runoff is apparent Even the variations of pH, SO42-, Ca2+ in total runoff of EB3 are triggered by the event rainfall, but the resultant variations appear much simpler than various curves of Hydrohill and monoliths This implies that only a simple process (i.e., mainly the hydrological process is involved in EB3) So, the complex diel varia‐ Current Challenges in Experimental Watershed Hydrology http://dx.doi.org/10.5772/55087 tions of the runoff responses from Hydrohill and monoliths (Figure 19) can be reasoned as the results of multi-coupling among hydrological, biological, and geochemical processes It shows that the reactor II (Figure 4) provides a key operator in contaminant hydrology 5.5 Runoff generation The measurements of various runoff components, within artificial systems containing controlled boundaries, provide the possibility to look inside the formation mechanisms of individual components Isotopic and geochemical tracing can help to investigate these mechanisms but only if significant differences in isotopic compositions of components occur The general mechanisms for these runoff components (i.e., the surface runoff, interflow and groundwater flow (saturated flow) ) are discussed in the following paragraphs [61,62] Surface runoff (SR) Precipitation input is, of course, the essential condition for the generation of surface runoff However, in order to actually generate runoff, there must be enough precipitation to form a thin, saturated soil layer (Lsat) at the ground surface Saturation is key because unsaturated water movement is thought to be too slow to generate runoff The thickness of Lsat at catchments, monoliths and plots was found to vary between to 50 mm throughout events, increasing downward during rainfall events and receding once rainfall stopped, although these findings were complicated by the irregularities of the soil surface SR was not generated until a Lsat was established at the surface Once a Lsat was developed, regardless of its thickness, SR was generated immediately Overland flow was only observed on impermeable surface (DO) at artificial plot and, on saturated surface (SO) from a special lysimeter designed for Lsat simulation Intrastorm variation of isotopic composition of DO and SO can match that of event rainfall In most cases however, SR is generated within the Lsat, with turbulent mixing of event and pre-event water stored in Lsat, i.e., the saturated mixing surface flow (MS); Alternatively, small amounts of event water act on the surface of Lsat, to force out pre-event water in the Lsat, termed here as the saturated expelled surface flow (ES) The isotopic composition of MS shows a mixing of event rainfall and pre-event water in Lsat The isotopic composition of ES is similar to that of Lsat Interflow (IF) in the unsaturated zone Three generation mechanisms are observed (1) In cases there are soil layers with distinct bulk density and/or hydraulic conductivities, IF can be generated at the interface of soil layers This was only observed in the ‘mini CZEB’, Nandadish, where IF occurred at the interface of the layers A (topsoil) and B (subsoil) This is termed as layered interflow (LI) (2) During percolation, soil water moves downward and laterally towards the drainage interface and accumulated until saturation The saturation will expand if the soil matrix potential ψ