Watershed Planning Research Articles

Uncertainty based assessment of dynamic freshwater scarcity in semi-arid watersheds of Alberta, Canada

Abstract Study region Alberta, Canada. Study focus The security of freshwater supplies is a growing concern worldwide. Understanding dynamics of water supply and demand is the key for sustainable planning and management of watersheds. Here we analyzed the uncertainties in water supply of Alberta by building an agro-hydrological model, which accounts for major hydrological features, geo-spatial heterogeneity, and conflicts over water-food-energy resources. We examined the cumulative effects of natural features (e.g., potholes, glaciers, climate, soil, vegetation), anthropogenic factors (e.g., dams, irrigation, industrial development), environmental flow requirements (EFR), and calibration schemes on water scarcity in the dynamics of blue and green water resources, and groundwater recharge. New hydrological insights for the region Natural hydrologic features of the region create a unique hydrological system, which must be accurately represented in the model for reliable estimates of water supply at high spatial and temporal resolution. Accounting for EFR, increases the number of months of water scarcity and the population exposed. Severe blue water scarcity in spring and summer months was found to be due to irrigated agriculture, while in winter months it was mostly due to the demands of petroleum or other industries. We found over exploitation of the groundwater in southern subbasins and concluded that more detailed analysis on groundwater flow and connectivity is required. Our study provides a general and unified approach for similar analyses in other jurisdictions around the world.

Integrated watershed management in the Bow River basin, Alberta: experiences, challenges, and lessons learned

Alberta’s Bow River is heavily engineered and hard-working, supplying water to almost 1.5 million people, while meeting the needs of hydropower, agriculture, tourism and irrigation industries upstream and downstream of Calgary. Working together since 1992, the Bow River Basin Council, a voluntary multi-stakeholder organization, with government representatives at the table, has developed watershed management plans as decision-support tools; provided a forum for relationship and trust building; shared information; and co-generated knowledge. Difficult challenges became opportunities for collaborative learning by doing. The processes involved in integrated watershed management were as important as the plans that emerged. Implementing plan objectives remains the greatest challenge.

The integrated watershed management planning experience in Manitoba: the local conservation district perspective

Manitoba has abundant freshwater resources, and developing and implementing integrated watershed management plans is essential to ensure a healthy future. This article provides an assessment of progress in Manitoba since the early 1990s (Mitchell and Shrubsole, 1994) regarding integrated watershed management plans. It explains current conditions, including the structural framework, governance, public consultations and First Nations participation, along with examples of experiences, successes, failures, and lessons learnt. The Water Protection Act, proclaimed in 2006, empowered conservation districts to develop and implement integrated watershed management plans as the water planning authority, and represents the most significant change.

Development of a Component-Based Modeling Framework for Agricultural Water-Resource Management

Because hydrologic responses of an agricultural watershed are influenced by many natural and man-made factors including pond/reservoir, management practices, and/or irrigation/drainage, strategies of hydrological modeling for the watershed must be case-dependent and thus carefully designed to effectively reflect their roles as critical hydrologic components in simulation processes. In this study, we propose a component-based modeling framework that accommodates a flexible modeling approach to consider a variety of hydrologic processes and management practices, especially irrigation-reservoir operation and paddy-farming practices, in watershed-scale modeling. The objectives of this study are twofold: to develop a COmponent-based Modeling Framework for Agricultural water-Resources Management (COMFARM) using an object-oriented programming technique, and to evaluate its applicability as a modeling tool to predict the responses of an agricultural watershed characterized with diverse land uses in a case study. COMFARM facilitates quick and easy development of watershed-specific hydrologic models by providing multiple interchangeable simulation routines for each hydrologic component considered. COMFARM is developed with the JAVA programming language, using Eclipse software. The framework developed in this study is applied to simulating hydrologic processes of the Seon-Am irrigation-district watershed consisting primarily of reservoir-irrigated rice paddies in South Korea. The application study clearly demonstrates the applicability of the framework as a convenient method to build models for hydrologic simulation of an agricultural watershed. The newly developed modeling framework, COMFARM is expected to serve as a useful tool in watershed management planning by allowing quick development of case-oriented analysis tools and evaluation of management scenarios customized to a specific watershed.

Field investigations of the 2013–14 drought through quali-quantitative freshwater monitoring at the headwaters of the Cantareira System, Brazil

ABSTRACTIntegrating seasonal patterns of water availability and land-use/land-cover change is crucial in watershed planning. Often, these are not considered under hydrological extremes affecting decision making. This article presents results from a multi-site, nested catchment experiment carried out during a dry period in the Cantareira Water Supply System, South-East Brazil, linking quali-quantitative freshwater monitoring to land-use/land-cover change. Results from 17 catchments show regional behaviour for nitrate loads and drainage areas (0.66–925 km2). An inverse correlation between forest cover and water yield was observed. Despite forest growth in spatial extent, nutrient loads showed potential hazards for water security.

CARACTERÍSTICAS DA PRECIPITAÇÃO PLUVIAL E A EROSIVIDADE DAS CHUVAS NA VERTENTE PARANAENSE DA BACIA HIDROGRÁFICA DO RIO ITARARÉ

Informações sobre do potencial erosivo das chuvas são necessárias para a prevenção e controle da degradação do solo, bem como no planejamento e desenvolvimento de bacias hidrográficas em regiões tropicais. O presente trabalho objetivou caracterizar a precipitação pluvial e quantificar o poder erosivo das chuvas na vertente paranaense da bacia hidrográfica do rio Itararé, dada a relevância para o manejo adequado e a aplicação de práticas preditivas a perda de solos. Foram obtidos os dados de treze postos pluviométricos e de uma estação meteorológica, de Joaquim Távora, pertencente ao Instituto Agronômico do Paraná, para a série histórica de 1976 a 2012. O índice de erosividade da chuva foi calculado utilizando-se uma equação do tipo a + bx, no qual a e b = coeficientes linear e angular, e x = p2/P (p – precipitação média mensal em milímetros; P – precipitação média anual em milímetros). Os resultados indicaram que o verão e a primavera caracterizam-se por apresentar a maior suscetibilidade a erosividade das chuvas devido a uma concentração de 70,8% dos valores anuais. Foram obtidas quatro regiões homogêneas quanto ao potencial erosivo das chuvas, demonstrando as relações entre a orografia e a dinâmica atmosférica regional.

THREE BAYS ESTUARY (BARNSTABLE, CAPE COD) WATERSHED RESTORATION PLAN: A GREEN INFRASTRUCTURE APROACH

INTRODUCTION This paper presents an approach described as “non-traditional” for restoring water quality and ecosystem services that have been degraded as a result of excess nitrogen. It focuses on emerging technologies often referred to as green infrastructure. These technologies may provide cost effective alternatives to traditional, gray infrastructure such as sewering and is likely to provide significant co-benefits including the creation of local jobs, the preservation of real estate values, and habitat enhancement. The paper focuses on the Three Bays estuary on Cape Cod to illustrate the benefits and potential of green infrastructure technologies. The Three Bays estuary is presented as a case study and as a representative example of implementation of the broader Cape Cod Water Quality Management Plan Update (208 Plan Update) – a nationally-recognized watershed planning project designed to provide a pathway for the fifteen towns of Cape Cod to achieve compliance with Section 208 of the Clean Water Act. The Three Bays estuary and embayment system is a scenic Cape Cod bay that hosts sailing, kayaking, swimming and shellfishing and is located in the Town of Barnstable. It is comprised of three primary segments that include West Bay, North Bay and Cotuit Bay. Sub-systems include Prince Cove that flows into North Bay, the Narrows that flows between North Bay and Cotuit Bay and Eel Pond that flows into East Bay (see Figure 1). The Massachusetts Estuaries Project (MEP) is a state-sanctioned watershed-modeling project that assesses the conditions of the state's estuaries and required restoration goals. Its technical report (2006) indicates that the water quality of the Three Bays system has resulted in seriously degraded to moderately degraded habitat. The system is listed as an impaired water body on the US Environmental Protection Agency (EPA) 303d list of impaired waters. An approved Total Maximum Daily Load (TMDL) for nitrogen has been established for the embayment. This assessment is supported by more recent empirical water quality data collected within the embayment. The more current data documents a continuing decline in water quality with more common algae blooms (see Figure 2).

Trajectories, drivers, and probabilities of land cover change in a disturbed forested watershed in eastern Taiwan

Understanding the trajectories, drivers, and probabilities of land cover change can provide essential information for forested watershed planning and sustainable management. This paper demonstrates that the Taimali watershed in eastern Taiwan underwent a dramatic decrease in forest cover under the influences of frequent earthquakes and typhoons during 2005–2011. To grasp the dynamics of land cover change, this study applied a combined land-change analysis approach using trajectory analysis and logistic regression. The results of trajectory analysis indicate that three change trajectories, covering 75.65 % of the total changed area, were considered the major trends of alterations, including the trajectories of Forest-Landslide, Forest-Channel, and vegetation recovery. Based on the causes of land conversion, most land transformation resulted from natural causes. Therefore, natural forces play a pivotal role in land cover change in the Taimali watershed. The results of logistic regression analysis show that lithology is the most important spatial determinant for occurrence probability of three change trajectories, followed by aspect and slope. Three maps of occurrence probability of the change trajectories were produced using regression coefficients. With the validation of the relative change intensity index, the results reveal that the observed change trajectories considerably coincided with the zones that had higher probabilities of change and covered a small area. Thus, three spatial statistical models are helpful tools for projecting the occurrence probabilities of the change trajectories.

Temporal Trends in the Spatial Distribution of Impervious Cover Relative to Stream Location

AbstractUse of impervious cover is transitioning from an indicator of surface water condition to one that also guides and informs watershed planning and management, including Clean Water Act (33 U.S.C. §1251 et seq.) reporting. Whether it is for understanding surface water condition or planning and management, impervious cover is most commonly expressed as summary measurement (e.g., percentage watershed in impervious cover). We use the National Land Cover Database to estimate impervious cover in the vicinity of surface waters for three time periods (2001, 2006, 2011). We also compare impervious cover in the vicinity of surface waters to watershed summary estimates of impervious cover for classifying the spatial pattern of impervious cover. Between 2001 and 2011, surface water shorelines (streams and water bodies) in the vicinity of impervious cover increased nearly 10,000 km. Across all time periods, approximately 27% of the watersheds in the continental United States had proximally distributed impervious cover, i.e., the percentage of impervious cover in the vicinity of surface waters was higher than its watershed summary expression. We discuss how impervious cover spatial pattern can be used to inform watershed planning and management, including reporting under the Clean Water Act.

Watershed Planning and Management in Colorado

This paper discusses the manner in which Colorado organizes its water management according to hydrographic boundaries and offers suggestions for ways the state can strengthen its existing approaches. In particular it notes that water courts are organized by basin, that the basins are now represented by roundtables, and that many water organizations are organized hydrologically. It discusses ways this basin approach could be strengthened within state government.

Adaptive Management in Water Law: Evaluating Australian (New South Wales) and Canadian (British Columbia) Law Reform Initiatives

Sub-national jurisdictions are undertaking law reform that attempts to remedy the historic inflexibility in water law and to provide security in water use entitlements. These reforms respond to increasing hydrological variability in many watersheds where the volume of water available for consumption at the times of highest demand is decreasing and minimum environmental flows are a precursor to healthy ecological systems. Adaptive management is a foundational ecological and ecosystem-based management principle. Scholars and professionals from a myriad of disciplines are calling for legal and policy structures that allow adaptive environmental management regimes based on evolving watershed conditions. Adaptive management in a water context requires integrated decision- making that incorporates land use decisions with decisions about surface and groundwater, provision for minimum environmental flows, and the ability to alter water users’ entitlements when a water resource is either over-allocated or changing flow regimes results in insufficient water. The purpose of this paper is to compare the water law reforms of the state of New South Wales in Australia and the province of British Columbia in Canada as they attempt to incorporate legal and management tools for adaptive management and to address fixed entitlements for water use in favour of more responsive and watershed-specific management approaches. In New South Wales, adaptation in water law is based on a watershed plan and allocation of a fluctuating consumptive pool of water, which is the amount of water available for extraction under licence after environmental needs are taken into account. In British Columbia, the provincial government may adapt water licences over time through water sustainability planning and water licence review, as well as issue short-term orders restricting water diversions without needing to compensate licence holders for any damages owing from these orders. These reforms are leading the restructuring of water law to address conflicts between water users as well as between water users and the environment. These reforms are also at the forefront internationally as models for adaptive management. They provide some flexibility in accommodating environmental flows but decrease certainty for water users as hydrological systems change. Their relative successes in accounting for adaptation and healthy hydrological systems will be instructive to other jurisdictions as they move to align their water laws with principles of adaptive management.

Estimation of Soil Loss Under Changing Climatic Scenarios in Semi-Arid Watersheds

Spatial and temporal estimation of soil loss is very essential for the sustainable planning and management of watersheds. In the present study, an attempt was made to estimate the soil loss spatially and temporally using RUSLE from a dry semi-arid watershed (Goparajpalli in Warangal District) and a wet semi-arid watershed (Seethagondi in Adilabad District) under changing climatic scenarios using PRECIS data. In the dry semi-arid watershed, the annual rainfall varied from 390 to 1181 mm with a mean value of 735 mm and a mean erosivity of 6260 MJ mm/ha/h/y. The mean annual rainfall during the base line period (1961–1990), mid (2021–2050) and end centuries (2071–2098) in this watershed were 738, 835 and 777 mm, respectively. The mean erosivity during these periods were 5657, 9253 and 7170 MJ mm/ha/h/y and soil loss from crop land were 2.39, 4.02 and 3.14 t/ha/y, respectively. In the wet semi-arid watershed, the annual rainfall varied from 508 to 1351 mm with a mean value of 950 mm and a mean erosivity of 6789 MJ mm/ha/h/y. The mean annual rainfall during base line, mid and end centuries in this wet semi-arid watershed were 956, 1088 and 1124 mm and erosivities were 10547, 14437 and 14755 MJ mm/ha/h/y, respectively. Similarly, the soil loss from crop land during these periods were 9.18, 13.11 and 14.11 t/ha/y. Even though, the soil loss from the dry semi-arid watershed was relatively lower than the wet semi-arid watershed, it showed an increasing trend in the mid century and a decreasing trend in the end century whereas, in the wet semi-arid watershed, it showed an increasing trend in both mid and end centuries. Considerable spatial variation in the mean annual soil loss was observed in both the wet and dry semi-arid watersheds during base line period, mid and end centuries.

An Approach to Environmental Planning and Sustainable Management of Watersheds and Municipalities in Southeastern Brazil

Diagnosis of fragmentation and landscape sustainability conditions are essential to environmental planning and sustainable management of natural resources. Land use spatial patterns and landscape structural indexes (landscape metrics, Urbanity Index— UI, and Landscape Vulnerability Index—LVI) have been proposed to assess biodiversity conservation and ecological sustainability, provided by impact of land use at Middle Mogi Gua&#231u watershed and its seventeen municipalities, in 2009. Land use typologies and structural indexes values were obtained based on screen digitizing of LandSat-5 imagery, for 2009. Cluster analysis and Permutational Multivariate Analysis of Variance were used to test the null hypothesis of equal degrees of fragmentation and sustainability conditions among municipalities in 2009, respectively. Land use spatial pattern showed a predominantly human occupation for watershed and its municipalities, with agricultural use as the main pressure factor. Municipalities were aggregated into three clusters related to forest fragmentation: one categorized by fifteen municipalities; the second cluster (municipality of Luiz Ant&#244nio) showing the best condition, and the third group (municipality of Araraquara) with extreme fragmentation condition. Landscape metrics related with shape, size, and core areas fragments intensify edge effects, and increase habitat isolation. The watershed showed a low naturalness and an intermediate degree of vulnerability. Ecological sustainability was different among municipalities (α = 0.05, F = 32.65 and p = 0.002), with two municipalities (Analandia and Luiz Ant&#244nio) presenting the best conditions. The most committed condition was observed, in municipalities of Rinc&#227o and Guatapara. For conservation policies to be effective must focus on the creation of ecological corridors around legally protected areas, besides creation of new legal reserves, with purpose to improve biodiversity conservation and ecological sustainability of Middle Mogi Gua&#231u watershed and its municipalities.

Environmental education for sustainable management of the basins of the rivers Pirapó, Paranapanema III and Parapanema IV

The growing concern about the quantity and quality of water has led managers and researchers from various countries to concentrate efforts in the study, planning and management of watersheds, considered appropriate units for the rational and sustainable management of water resources. This experience report presents results of the Program for Communication, Environmental Education and Social Mobilization, which is part of the project "Monitoring Network of the basins of the rivers Pirapó, Paranapanema III and Paranapanema IV - analysis and monitoring of the hydrological behavior", developed by a multidisciplinary team of researchers and graduate students of the State University of Maringá (Paraná, Brazil). The goals of the program were: a) To develop continuing education for teachers of basic education, active in state schools located in the basins studied; b) To raise awareness and to promote training of various local social actors; c) To produce educational and promotional materials for teachers and general community, respectively. The methodology was the action research, on the basis of collaborative work between university researchers and participants of the program. The results evidence that teachers and representatives of different social groups had a limited view of issues related to water resources of their region. Courses, workshops and itinerant exhibitions, beyond teaching aids and promotional material prepared by the group of researchers and graduate students contributed to broaden the view of social actors about watersheds to which they are part, from the perspective of an active, critical and responsible participation focused on sustainable use and management of water resources.

Is Information Enough? The Effects of Watershed Approaches and Planning on Targeting Ecosystem Restoration Sites

Since 1996, the watershed approach (i.e., the inclusive use of watershed information) has been a hallmark concept in ecosystem restoration site location. In 2008, federal regulators required use of the watershed approach in siting compensatory mitigation for aquatic impacts regulated under the U.S. Clean Water Act. However, regulations fell short of requiring full watershed plans, which could have required stakeholder involvement and inter-institutional coordination. Little work has evaluated how the watershed approach or planning position mitigation sites in the landscape. Has the watershed approach or watershed planning been successful in targeting restoration sites where they are needed? The North Carolina Division of Mitigation Services (DMS; formerly the NC Ecosystem Enhancement Program), a state agency, has implemented the watershed approach and extensive watershed planning to focus restoration investments. Through a multi-step planning program, the DMS employs a watershed approach to gauge the need of 12-digit watersheds for restoration. In some cases, an intensive local watershed planning process follows this targeting effort. We tested the effect of the program’s watershed targeting approach (n = 710) and local watershed planning efforts (n = 147) on increasing the frequency of wetland and stream mitigation projects (n = 480) in each of the state’s 1741 12-digit watersheds (1998–2012). We find that while the watershed approach is successful at guiding restoration to targeted watersheds over space and time, the impacts of watershed planning are more nebulous, with important but weaker panel-effects. Our findings highlight the importance of plan quality and data management in using a watershed approach to target restoration sites effectively.

Stakeholder Participation in Collaborative Watershed Planning in Washington State

Stakeholder participation in collaborative watershed planning in Washington State was examined in three watershed planning unit cases in order to understand how stakeholders participate in collaborative watershed planning, the nature of plans developed, and stakeholder perceptions of plan implementation. Through document analysis and interviews, we found broad and inclusive representation of stakeholders in the planning processes, and that a majority of stakeholder comments were reflected in the final plans. Plans were of good quality and provide a strong foundation for implementation. Factors that facilitate plan implementation include the collaborative planning process itself, funding and community support, and leadership along with early and sustained involvement. Factors that hinder plan implementation include lack of adequate funding, various legal issues, and challenges in involving landowners in plan projects.

Evaluation of the AnnAGNPS Model for Predicting Runoff and Nutrient Export in a Typical Small Watershed in the Hilly Region of Taihu Lake.

The application of hydrological and water quality models is an efficient approach to better understand the processes of environmental deterioration. This study evaluated the ability of the Annualized Agricultural Non-Point Source (AnnAGNPS) model to predict runoff, total nitrogen (TN) and total phosphorus (TP) loading in a typical small watershed of a hilly region near Taihu Lake, China. Runoff was calibrated and validated at both an annual and monthly scale, and parameter sensitivity analysis was performed for TN and TP before the two water quality components were calibrated. The results showed that the model satisfactorily simulated runoff at annual and monthly scales, both during calibration and validation processes. Additionally, results of parameter sensitivity analysis showed that the parameters Fertilizer rate, Fertilizer organic, Canopy cover and Fertilizer inorganic were more sensitive to TN output. In terms of TP, the parameters Residue mass ratio, Fertilizer rate, Fertilizer inorganic and Canopy cover were the most sensitive. Based on these sensitive parameters, calibration was performed. TN loading produced satisfactory results for both the calibration and validation processes, whereas the performance of TP loading was slightly poor. The simulation results showed that AnnAGNPS has the potential to be used as a valuable tool for the planning and management of watersheds.

Watershed Plan Implementation Challenges for SMS4s in Murrells Inlet

This case study describes the plan development process, implementation strategies and initial and future challenges to implementation for the Murrells Inlet Watershed Plan (WRCOG, 2014). The Plan was crafted by a group of key stakeholders with community support and guidance to address fecal coliform bacteria loading in shellfish harvesting waters in the Murrells Inlet Estuary along the northeastern South Carolina coast. Stakeholders debated the interpretation of the data analysis and ultimately concluded that the primary pollutant sources were non-human, namely wildlife and domestic animals. Stakeholders also concluded that the loads from these sources were being delivered to the estuary via a landscape that includes a network of surface drainage ditches and subsurface pipes so that water retention on the landscape has been largely short-circuited. Armed with this information, plan participants devised management measures that encompass several strategies, including: (1) utilize an end-of-pipe/ditch solution that addresses pollution nearest the discharge point; (2) generally reduce volume and flow and/or increase retention/detention across the landscape to reduce the pollutant load; and (3) use education and outreach to achieve behavior change. During both plan development and the implementation of management measures, the plan steering committee faced significant challenges. Initial challenges include: geographic and space limitations that make the use of large retention or detention devices impractical; lack of state or local requirements to use low impact development techniques to increase retention; and mounting outreach campaigns that cannot guarantee significant pollution reductions. Additional complications include mechanisms to sustain community support and involvement. As implementation progresses, the steering committee must track plan implementation and determine creative ways to evaluate the effectiveness of management measures. Local funding allocations must also be sought to leverage against potential grant funds to enable implementation.

Agricultural conservation planning framework: 1. Developing multipractice watershed planning scenarios and assessing nutrient reduction potential.

Spatial data on soils, land use, and topography, combined with knowledge of conservation effectiveness, can be used to identify alternatives to reduce nutrient discharge from small (hydrologic unit code [HUC]12) watersheds. Databases comprising soil attributes, agricultural land use, and light detection and ranging-derived elevation models were developed for two glaciated midwestern HUC12 watersheds: Iowa's Beaver Creek watershed has an older dissected landscape, and Lime Creek in Illinois is young and less dissected. Subsurface drainage is common in both watersheds. We identified locations for conservation practices, including in-field practices (grassed waterways), edge-of-field practices (nutrient-removal wetlands, saturated buffers), and drainage-water management, by applying terrain analyses, geographic criteria, and cross-classifications to field- and watershed-scale geographic data. Cover crops were randomly distributed to fields without geographic prioritization. A set of alternative planning scenarios was developed to represent a variety of extents of implementation among these practices. The scenarios were assessed for nutrient reduction potential using a spreadsheet approach to calculate the average nutrient-removal efficiency required among the practices included in each scenario to achieve a 40% NO-N reduction. Results were evaluated in the context of the Iowa Nutrient Reduction Strategy, which reviewed nutrient-removal efficiencies of practices and established the 40% NO-N reduction as Iowa's target for Gulf of Mexico hypoxia mitigation by agriculture. In both test watersheds, planning scenarios that could potentially achieve the targeted NO-N reduction but remove <5% of cropland from production were identified. Cover crops and nutrient removal wetlands were common to these scenarios. This approach provides an interim technology to assist local watershed planning and could provide planning scenarios to evaluate using watershed simulation models. A set of ArcGIS tools is being released to enable transfer of this mapping technology.

Effects of Climate and Land Cover on Hydrology in the Southeastern U.S.: Potential Impacts on Watershed Planning

AbstractThe hydrologic response to statistically downscaled general circulation model simulations of daily surface climate and land cover through 2099 was assessed for the Apalachicola‐Chattahoochee‐Flint River Basin located in the southeastern United States. Projections of climate, urbanization, vegetation, and surface‐depression storage capacity were used as inputs to the Precipitation‐Runoff Modeling System to simulate projected impacts on hydrologic response. Surface runoff substantially increased when land cover change was applied. However, once the surface depression storage was added to mitigate the land cover change and increases of surface runoff (due to urbanization), the groundwater flow component then increased. For hydrologic studies that include projections of land cover change (urbanization in particular), any analysis of runoff beyond the change in total runoff should include effects of stormwater management practices as these features affect flow timing and magnitude and may be useful in mitigating land cover change impacts on streamflow. Potential changes in water availability and how biota may respond to changes in flow regime in response to climate and land cover change may prove challenging for managers attempting to balance the needs of future development and the environment. However, these models are still useful for assessing the relative impacts of climate and land cover change and for evaluating tradeoffs when managing to mitigate different stressors.