Watershed Water Research Articles

Restoring the Greater: Everglades Ecosystem

Restoring the Greater: Everglades Ecosystem

A Stakeholder-Guided Collaborative Approach to Improve Water Quality in a Nutrient Surplus Watershed

The need for water quality improvement in nutrient surplus watersheds is a pressing issue on the agenda of some government agencies and environmental organizations. Including the water quality perceptions of different affected stakeholder groups in the decision-making process may help in addressing this issue. Unfortunately, there is a lack of published research focusing specifically on understanding how Arkansas stakeholders’ perceptions of water quality issues can be used to build and implement comprehensive and workable water quality management plans. Therefore, the objective of this study was to use a stakeholder-guided collaborative approach to help research and outreach personnel to understand water quality perceptions of key stakeholders and to integrate stakeholder engagement in both the decision-making process and in the implementation of water quality management strategies within the Lincoln Lake Watershed in northwest Arkansas. Two key stakeholder groups (i.e., Locals—residents and agricultural producers—and Outsiders—water quality specialist across the state) were surveyed to assess their perceptions regarding: 1) causes of watershed water quality problems, 2) parties responsible for water quality improvement, 3) effectiveness and affordability of best management practices to reduce water quality degradation, and 4) the stakeholders’ interactions with county, state and federal government. A total of 209 complete surveys (49% response rate) were received. Survey responses were compared to determine if significant differences existed between the two stakeholder groups’ perceptions of water quality performing Fisher’s exact tests. Results from the study showed that water quality is still perceived as an issue in the Lincoln Lake Watershed. Significant differences were found between the two stakeholder groups’ perceptions regarding: 1) different groups’ contributions to water degradation, 2) groups’ responsibilities for cleanup, 3) effectiveness of five best management practices, 4) affordability of four best management practices, and 5) what level of government (i.e., county, state, federal) best represents Locals’ water quality needs and concerns. The lessons learned from this collaborative approach helped identifying Locals’ important knowledge gaps regarding water quality and best management practices effectiveness. Consequently, awareness and education campaigns in conjunction with a stewardship recognition program were conducted to encourage appropriate water conservation strategies within the Lincoln Lake watershed and its adjacent areas.

Microbial investigations of water, sediment, and algal mats in the mixed use watershed of Saginaw Bay, Michigan

Beach monitoring often includes testing for a single fecal indicator organism in the swimmable waters. Here, sediment, algae mat, shallow water, and deep water samples collected from four Saginaw Bay (Michigan, USA) beaches were tested for multiple fecal indicator organisms (Escherichia coli, enterococci, Clostridium perfringens, F+amp coliphage, and CN-13 coliphage) and molecular markers (human and bovine Bacteroides and enterococci surface protein) to determine the occurrence and sources of fecal indicator bacteria across beachscapes and characterize the environmental parameters which influence microbial water quality. Results show algae mats and sediment had higher levels of bacteria compared to surrounding water column. Higher concentrations of fecal indicators in shallow waters compared to deep water were attributed in part to sediment and algae bound bacteria and potential regrowth. Fecal indicator organisms were primarily influenced by wind, waves, and precipitation and partially identified as human specific using the enterococci surface protein gene. This project suggests the potential for sediment and algal mats to act as non-point sources of pollution in the nearshore zone. Future beach protection measures should focus on shallow water monitoring of multiple fecal indicators and beach grooming during calm morning hours.

Evaluation of mixed forest evapotranspiration and soil moisture using measured and swat simulated results in a hillslope watershed

This study evaluated SWAT model when measured Evapotranspiration (ET) and Soil Moisture (SM) in addition to streamflow (Q) data were used to calibrate the simulated values in a 8.54 km2 hillslope watershed of South Korea. By using 7 years (2003–2009) daily Q at the watershed outlet, 3 years (2007–2009) daily ET and SM data measured in the mixed forest, the SWAT model was calibrated and validated with the average Nash-Sutcliffe model efficiency (E) for Q of 0.76, and the coefficient of determination (R2) for SM and ET of 0.55 and 0.59, respectively. The use of measured hydrological state variables such as ET or SM in SWAT modeling provided more reliable interpretation of model parameters by inducing the reduction of parameter uncertainty and understanding the behavior of the watershed water balance. When the watershed has only Q data for model calibration, it is encouraged to consider soil (ESCO) and plant related parameters (EPCO and CANMX) in addition to surface runoff (CN2, and Surlag) and groundwater related parameters (GW_ DELAY and GW_ REVAP).

Temporal variability of rainfall in a semiarid environment in Brazil and its effect on sediment transport processes

The temporal variabilities of both soil erosion by water and sediment redistribution in watersheds are directly related to rainfall characteristics. The purpose of this work was to assess the temporal pattern of rainfall in a semiarid watershed in Brazil and explain how this feature controls soil erosion and sediment yield. Daily and 5-min rainfall records were used to assess the temporal pattern down to the sub-hourly scale. To study the effect of the rainfall on sediment processes, erosivity and sediment yield at the Aiuaba (12 km2) and Bengue (933 km2) watersheds, Brazil were determined. Erosivity was calculated based on the rainfall kinetic energy method, while sediment yield was estimated from sediment rating curves and daily water discharge measurements. A large portion of annual rainfall is restricted to a few rain events and strong concentration in the sub-daily scale occurs, producing high erosivity. The temporal concentration of erosivity is greater than that of rainfall; the 10th percentile of the highest magnitude events encompasses 51% of the precipitation, but 80% of the erosivity. The temporal concentration of sediment yield is more pronounced; 88 and 98% of the sediment yield for the Aiuaba and Bengue watersheds, respectively, are within the 10th percentile of events. The strong temporal concentration of precipitation causes events with high intensity and erosivity, thus allowing for soil detachment. Nonetheless, the low runoff rates limit downstream sediment transport. Such behavior produces a much higher temporal concentration of sediment yield, which reaches its maximal after a sequence of rainy days, when hydrological connectivity is enhanced and the sediments are propagated throughout the entire transport-limited system.

Resolution of Respect: F. Herbert Bormann 1922–2012

Resolution of Respect: F. Herbert Bormann 1922–2012

Differences in Opinions about Surface Water Quality Issues in the Southern United States: Implications for Watershed Planning Process

Public participation in a watershed planning process involves reaching out to social groups with very diverse opinions and perceptions about environmental issues. Using responses to a nationwide survey of public attitudes and perceptions related to water issues, we examined the effects of socio-demographic and residence characteristics on opinions about water quality, agricultural and urban pollution sources, and nutrients and pathogen pollution issues in the southern United States. Significant differences were identified among respondents of different age groups, genders, and educational levels. Opinions also differed significantly among urban and rural respondents and between states. These results can be used by state and local agencies, universities, and extension services involved in the design of collaborative watershed management processes and water resource educational efforts.

수질오염총량 단위유역별 LDC(Load Duration Curve, 부하지속곡선) 적용을 통한 수질관리 대안 모색 - 금호강 유역 대상

【This study was to develop effective water quality management measures using LDC (Load Duration Curve) curves for TMDL (Total Maximum Daily Loads) unit watershed. Using LDC curves, major factors for BOD and T-P concentration loads generation (i.e. point source or non-point source) in the case study area (Geumho river basin) were found for different hydrologic conditions. Different measures to deal with the pollutant loads were suggested to establish BMPs (Best Management Practices). It was found that the target area has urgent T-P management methods especially at moist and midrange hydrologic conditions because of point source pollutants occurred in developed areas. One example measure for this could be establishment of advanced treatment facility. This study proved that the use of LDC was a useful way to achieve TWQ (Target Water Quality) on the target watershed considered. It was also expected that the methodology applied in this study could have a wider application on the establishment of watershed water management measures.】

Dryness of ephemeral lakes and consequences for dust activity: The case of the Hamoun drainage basin, southeastern Iran

This study examines the influence of changes in the water coverage in the Hamoun dry-bed lakes on visibility, dust outbreaks, aerosol loading and land–atmospheric fluxes over the region covering the period 1985–2005. The Hamoun basin, located on the southeastern Iran and western Afghanistan borders, has been recognized as one of the major dust source regions in south Asia and is covered by shallow, marshy lakes that are fed by the Helmand and Farahrood rivers. When the water in watersheds that support the lakes is drawn down for natural or human-induced reasons, the end result is a decrease in the water coverage in the basin, or even complete dryness as occurred in 2001. Then, strong seasonal winds, mainly in summer, blow fine sand and silt off the exposed lakebed, enhancing dust activity and aerosol loading over the region. Satellite (Landsat) and meteorological observations reveal that the water levels in the Hamoun lakes exhibit considerable inter-annual variability during the period 1985–2005 strongly related to anomalies in precipitation. This is the trigger for concurrent changes in the frequency of the dusty days, aerosol loading and deterioration of visibility over the region, as satellite (TOMS, MODIS, MISR) observations reveal. On the other hand, soil moisture and latent heat, obtained via model (GLDAS_noah-10) simulations are directly linked with water levels and precipitation over the region. The desiccation of the Hamoun lakes in certain years and the consequent increase in frequency and intensity of dust storms are serious concerns for the regional climate, ecosystems and human health.

Measuring Environmental Sustainability of Water in Watersheds

Environmental sustainability assessment is a rapidly growing field where measures of sustainability are used within an assessment framework to evaluate and compare alternative actions. Here we argue for the importance of evaluating environmental sustainability of water at the watershed scale. We review existing frameworks in brief before reviewing watershed-relevant measures in more detail. While existing measures are diverse, overlapping, and interdependent, certain attributes that are important for watersheds are poorly represented, including spatial explicitness and the effect of natural watershed components, such as rivers. Most studies focus on one or a few measures, but a complete assessment will require use of many existing measures, as well as, perhaps, new ones. Increased awareness of the broad dimensions of environmental sustainability as applied to water management should encourage integration of existing approaches into a unified assessment framework appropriate for watersheds.

Adaptivity of Budyko Hypothesis in Evaluating Interannual Variability of Watershed Water Balance in Northern China

AbstractThis study evaluates the performance of three Budyko-type equations (Fu’s equation, Turc-Pike’s equation, and Milly’s equation) in modeling annual evapotranspiration in 32 watersheds covering both humid and arid regions in Northern China. Daily meteorological data and monthly runoff data are used to calculate potential and actual evapotranspirations in the 32 watersheds. The results show that the Budyko-type equations are adaptive in predicting annual evapotranspiration over most of the watersheds, and Fu’s and Turc-Pike’s equations perform better than Milly’s. In addition, the validity of the framework by Koster and Suarez in predicting the evapotranspiration deviation ratio (EDR) (i.e., the ratio of the standard deviation of evapotranspiration to the standard deviation of rainfall) based on Fu’s and Ture-Pike’s equations is also examined. Given the unexpected Nash–Sutcliffe efficiency values (−0.915 and −1.026 in Fu’s and Ture-Pike’s, respectively), a linear one-variable model is employed to imp...

Causes and Consequences of Ecosystem Service Regionalization in a Coastal Suburban Watershed

The demand for ecosystem services and the ability of natural ecosystems to provide those services evolve over time as population, land use, and management practices change. Regionalization of ecosystem service activity, or the expansion of the area providing ecosystem services to a population, is a common response in densely populated coastal regions, with important consequences for watershed water and nitrogen (N) fluxes to the coastal zone. We link biophysical and historical information to explore the causes and consequences of change in ecosystem service activity—focusing on water provisioning and N regulation—from 1850 to 2010 in a coastal suburban watershed, the Ipswich River watershed in northeastern Massachusetts, USA. Net interbasin water transfers started in the late 1800s due to regionalization of water supply for use by larger populations living outside the Ipswich watershed boundaries, reaching a peak in the mid-1980s. Over much of the twentieth century, about 20 % of river runoff was diverted from reaching the estuary, with greater proportions during drought years. Ongoing regionalization of water supply has contributed to recent declines in diversions, influenced by socioecological feedbacks resulting from the river drying and fish kills. Similarly, the N budget has been greatly perturbed since the suburban era began in the 1950s due to food and lawn fertilizer imports and human waste release. However, natural ecosystems are able to remove most of this anthropogenic N, mitigating impacts on the coastal zone. We propose a conceptual model whereby the amount and type of ecosystem services provided by coastal watersheds in urban regions expand and contract over time as regional population expands and ecosystem services are regionalized. We hypothesize that suburban watersheds can be hotspots of ecosystem service sources because they retain sufficient ecosystem function to still produce services that meet increasing demand from the local population and nearby urban centers. Historical reconstruction of ecosystem service activity provides a perspective that may help to better understand coupled human–natural system processes and lead to more sustainable management of coastal ecosystems.

The Research of Decentralized Wastewater Treatment Mode in Rural Areas in China

With the implementation of new rural development policy and development of rural economic in China, water pollution becomes a serious problem in rural areas, which has been the major factor that leads to watershed quality deterioration and ground water pollution. It should adjust measures to local condition to use decentralized wastewater treatment mode in rural area in China. Basing on current situation and characterization of wastewater discharge in rural areas, the characterization, application and development of decentralized wastewater treatment in the worldwide were reviewed. Major problems encountered in its design and operation processes were discussed, solution measures were also given combining the actual condition in rural areas.

A variable source area for groundwater evapotranspiration: impacts on modeling stream flow

AbstractEvapotranspiration (ET) plays a crucial role in catchment water budgets, typically accounting for more than 50% of annual precipitation falling within temperate deciduous forests. Groundwater ET is a portion of total ET that occurs where plant roots extend to the capillary fringe above the phreatic surface or induce upward movement of water from the water table by hydraulic redistribution. Groundwater ET is spatially restricted to riparian zones or other areas where the groundwater is accessible to plants. Due to the difficulty in measuring groundwater ET, it is rarely incorporated explicitly into hydrological models. In this study, we calibrated Topographic Model (TOPMODEL) using a 14‐year hydrograph record and added a groundwater ET pathway to derive a new model, Groundwater Evapotranspiration TOPMODEL (GETTOP). We inspected groundwater elevations and stream flow hydrographs for evidence of groundwater ET, examined the relationship between groundwater ET and topography, and delineated the area where groundwater ET is likely to take place. The total groundwater ET flux was estimated using a hydrological model. Groundwater ET was larger where the topography was flat and the groundwater table was shallow, occurring within about 10% of the area in a headwater catchment and accounting for 6 to 18% of total annual ET. The addition of groundwater ET to GETTOP improved the simulation of stream discharge and more closely balanced the watershed water budget. Copyright © 2013 John Wiley & Sons, Ltd.

Assessment of nitrogen and phosphorus loads and causal factors from different land use and soil types in the Three Gorges Reservoir Area

It is important to identify nitrogen (N) and phosphorus (P) from non-point sources (NPS) to protect watershed water quality. However, few studies have been conducted in a large basin to determine the sources and causal factors of N and P from multiple land use and soil types. In this study, the Soil and Water Assessment Tool (SWAT) was applied in support of the Small-scale Watershed Extended Method (SWEM) in the Three Gorges Reservoir Region (TGRR), China. The first-order error analysis (FOEA) was used to identify the key sub-processes that affected the occurrence of NPS pollution. Based on this study, runoff from the dry land and paddy fields was enriched with nutrients, while runoff from purplish soils, paddy soils and yellow earths made up the largest amount of nutrient loads. The results showed that the contributions of individual parameters to the total uncertainty were different among land use and soil types. This study indicated that management efforts for dry land must explicitly account for conservation practices and proper land covers, while conscientious fertilization practices would result in a greater decrease of NPS yields for paddy fields. Grazing practices should be considered for the purpose of N management for yellow earths, while plant density is important to control soil erosion for purple soils.

Age distributions and dynamically changing hydrologic systems: Exploring topography‐driven flow

Key Points Age distributions evolve over time under transient flow conditions Transient flow leads to the emergence of new characteristic time scales in ADs Dynamic ADs impact the biogeochemical evolution of water in watersheds and HZs

Effects of critical source area on sediment yield and streamflow

AbstractThe spatial discretization scale determines the degree to which the spatial heterogeneity of the surface condition and the stream network can be represented. Discretization scale can have a significant impact on watershed model results, with respect to both hydrology and water quality. The impact of critical source area (CSA) on simulated water yield for each cell can be assessed for streamflow and run‐off using the Annualized Agricultural Non‐Point Source (AnnAGNPS) model. The total number of cells simulated for the six watersheds ranged from 8 to 352 for various CSA combinations. Increasing the number of subwatersheds increased water and sediment yield in many watersheds. Increasing the number of cells influences the depiction of land use and soil type accordingly and therefore influences run‐off. The applied CSAs were also compared with topographic parameters such as average cell slope, average channel slope and length to width ratio of each watershed.

Qualidade da água em microbacias hidrográficas com diferentes coberturas do solo no sul do Espírito Santo

O objetivo deste trabalho foi avaliar a qualidade das águas superficiais e subterrâneas em microbacias hidrográficas caracterizadas por diferentes coberturas do solo: pastagem, floresta e cafeeiro. Foi desenvolvido um índice de qualidade de água utilizando a análise de componentes principais, que proporcionou a redução das 13 características de qualidade em duas componentes, que explicaram 91,2% da variância total. As águas superficiais e subterrâneas das microbacias foram adequadas ao consumo humano, após tratamento convencional, ao longo de todo o período estudado, exceto a água subterrânea da microbacia coberta com pastagem no período de estiagem.

Constraining Nitrogen Inputs to Urban Streams from Leaking Sewers Using Inverse Modeling: Implications for Dissolved Inorganic Nitrogen (DIN) Retention in Urban Environments

Leaking sewer infrastructure contributes nonpoint nitrogen pollution to groundwater and surface water in urban watersheds. However, these inputs are poorly quantified in watershed budgets, potentially underestimating pollutant loadings. In this study, we used inverse methods to constrain dissolved inorganic nitrogen (DIN) inputs from sewage to Nine Mile Run (NMR), an urban watershed (1570 ha) in Pittsburgh, Pennsylvania (USA) characterized by extensive impervious surface cover (38%). Water samples were collected biweekly over two years and intensive sampling was conducted during one summer storm. A nitrogen budget for the NMR watershed was constructed, ultimately inverted, and sewage DIN inputs constrained using Monte Carlo simulation. Results reveal substantial DIN contributions from sewage ranging from 6 to 14 kg ha-1 yr-1. When conservative estimates of DIN from sewage are included in input calculations, DIN retention in NMR is comparable to high rates observed in other suburban/urban nutrient budgets (84%). These results suggest a pervasive influence of leaking sewers during baseflow conditions and indicate that sewage-sourced DIN is not limited to sewer overflow events. Further, they highlight the importance of sewage inputs to DIN budgets in urban streams, particularly as sewer systems age across the U.S.

下水処理場の流域における水・物質・エネルギー循環拠点化に関する研究

下水処理場の流域における水・物質・エネルギー循環拠点化に関する研究