The wilderness use simulation model applied to Colorado River boating in Grand Canyon National Park,USA

A modification of the Shechter-Lucas Wilderness Use Simulation Model (WUSM) for peak season boating on the Colorado River through Grand Canyon National Park, USA, is evaluated as a tool for making management decisions. A new microcomputer program to select trip itineraries for inclusion in the WUSM that was developed as part of this study is presented. This program simplifies user input and expands the WUSM's usefulness as a tool for management decisions by randomizing itinerary schedules based on probabilities developed from actual use of sites by canyon visitors. Model usefulness is demonstrated by simulating various management changes and comparing use levels of attraction sites and campgrounds as well as numbers of encounters between parties. The WUSM is being used as part of an ongoing study, to reflect the impact of fluctuating flow regimes through the turbines at Glen Canyon Dam on river trips.     

Regional economic impacts of Grand Canyon river runners

Economic impact analysis (EIA) of outdoor recreation can provide critical social information concerning the utilization of natural resources. Outdoor recreation and other non-consumptive uses of resources are viewed as environmentally friendly alternatives to extractive-type industries. While outdoor recreation can be an appropriate use of resources, it generates both beneficial and adverse socioeconomic impacts on rural communities. The authors used EIA to assess the regional economic impacts of rafting in Grand Canyon National Park. The Grand Canyon region of northern Arizona represents a rural US economy that is highly dependent upon tourism and recreational expenditures. The purpose of this research is twofold. The first is to ascertain the previously unknown regional economic impacts of Grand Canyon river runners. The second purpose is to examine attributes of these economic impacts in terms of regional multipliers, leakage, and types of employment created. Most of the literature on economic impacts of outdoor recreation has focused strictly on the positive economic impacts, failing to illuminate the coinciding adverse and constraining economic impacts. Examining the attributes of economic impacts can highlight deficiencies and constraints that limit the economic benefits of recreation and tourism. Regional expenditure information was obtained by surveying non-commercial boaters and commercial outfitters. The authors used IMPLAN input-output modeling to assess direct, indirect, and induced effects of Grand Canyon river runners. Multipliers were calculated for output, employment, and income. Over 22,000 people rafted on the Colorado River through Grand Canyon National Park in 2001, resulting in an estimated $21,100,000 of regional expenditures to the greater Grand Canyon economy. However, over 50% of all rafting-related expenditures were not captured by the regional economy and many of the jobs created by the rafting industry are lower-wage and seasonal. Policy recommendations are given for increasing the regional retention of rafting expenditures and for understanding both the beneficial and adverse impacts that accompany outdoor recreation in rural areas.     

Recreational impacts on backcountry campsites in Grand Canyon National Park,Arizona, USA

Backcountry campsites were studied in three desert vegetation types (pinyon-juniper, catclaw, and desert scrub) in Grand Canyon National Park, Arizona. Relationships between amount of use and amount of impact were examined within each vegetation type. The area disturbed was small, but impacts were generally severe. Important impacts were increased soil compaction and associated decreases in infiltration rates and soil moisture content; these were substantially more pronounced on high than low use sites. The only impact parameter that differed significantly between vegetation types was core area. The types of impact identified are similar to those found in the coniferous forests studied elsewhere, as is the logarithmic relationship between amount of use and amount of impact. However, Grand Canyon sites can support more visitor use before reaching near-maximum levels of impact for important impact parameters.     

Assessment of Coarse Sediment Mobility in the Black Canyon of the Gunnison River,Colorado

The Gunnison River in the Black Canyon of the Gunnison National Park (BCNP) near Montrose, Colorado is a mixed gravel and bedrock river with ephemeral side tributaries. Flow rates are controlled immediately upstream by a diversion tunnel and three reservoirs. The management of the hydraulic control structures has decreased low-frequency, high-stage flows, which are the dominant geomorphic force in bedrock channel systems. We developed a simple model to estimate the extent of sediment mobilization at a given flow in the BCNP and to evaluate changes in the extent and frequency of sediment mobilization for flow regimes before and after flow regulation in 1966. Our methodology provides a screening process for identifying and prioritizing areas in terms of sediment mobility criteria when more precise systematic field data are unavailable. The model uses the ratio between reach-averaged bed shear stress and critical shear stress to estimate when a particular grain size is mobilized for a given reach. We used aerial photography from 1992, digital elevation models, and field surveys to identify individual reaches and estimate reach-averaged hydraulic geometry. Pebble counts of talus and debris fan deposits were used to estimate regional colluvial grain-size distributions. Our results show that the frequency of flows mobilizing river bank sediment along a majority of the Gunnison River in the BCNP has significantly declined since 1966. The model results correspond well to those obtained from more detailed, site-specific field studies carried out by other investigators. Decreases in the frequency of significant sediment-mobilizing flows were more pronounced for regions within the BCNP where the channel gradient is lower. Implications of these results for management include increased risk of encroachment of vegetation on the active channel and long-term channel narrowing by colluvial deposits. It must be recognized that our methodology represents a screening of regional differences in sediment mobility. More precise estimates of hydraulic and sediment parameters would likely be required for dictating quantitative management objectives within the context of sediment mobility and sensitivity to changes in the flow regime.     

Reconciling Environmental and Flood Control Goals on an Arid-Zone River: Case Study of the Limitrophe Region of the Lower Colorado River in the United States and Mexico

Arid zone rivers have highly variable flow rates, and flood control projects are needed to protect adjacent property from flood damage. On the other hand, riparian corridors provide important wildlife habitat, especially for birds, and riparian vegetation is adapted to the natural variability in flows on these rivers. While environmental and flood control goals might appear to be at odds, we show that both goals can be accommodated in the Limitrophe Region (the shared border between the United States and Mexico) on the Lower Colorado River. In 1999, the International Boundary and Water Commission proposed a routine maintenance project to clear vegetation and create a pilot channel within the Limitrophe Region to improve flow capacity and delineate the border. In 2000, however, Minute 306 to the international water treaty was adopted, which calls for consideration of environmental effects of IBWC actions. We conducted vegetation and bird surveys within the Limitrophe and found that this river segment is unusually rich in native cottonwood and willow trees, marsh habitat, and resident and migratory birds compared to flow-regulated segments of river. A flood-frequency analysis showed that the existing levee system can easily contain a 100 year flood even if vegetation is not removed, and the existing braided channel system has greater carrying capacity than the proposed pilot channel.     

Analyzing the Impacts of Dams on Riparian Ecosystems: A Review of Research Strategies and Their Relevance to the Snake River Through Hells Canyon

River damming provides a dominant human impact on river environments worldwide, and while local impacts of reservoir flooding are immediate, subsequent ecological impacts downstream can be extensive. In this article, we assess seven research strategies for analyzing the impacts of dams and river flow regulation on riparian ecosystems. These include spatial comparisons of (1) upstream versus downstream reaches, (2) progressive downstream patterns, or (3) the dammed river versus an adjacent free-flowing or differently regulated river(s). Temporal comparisons consider (4) pre- versus post-dam, or (5) sequential post-dam conditions. However, spatial comparisons are complicated by the fact that dams are not randomly located, and temporal comparisons are commonly limited by sparse historic information. As a result, comparative approaches are often correlative and vulnerable to confounding factors. To complement these analyses, (6) flow or sediment modifications can be implemented to test causal associations. Finally, (7) process-based modeling represents a predictive approach incorporating hydrogeomorphic processes and their biological consequences. In a case study of Hells Canyon, the upstream versus downstream comparison is confounded by a dramatic geomorphic transition. Comparison of the multiple reaches below the dams should be useful, and the comparison of Snake River with the adjacent free-flowing Salmon River may provide the strongest spatial comparison. A pre- versus post-dam comparison would provide the most direct study approach, but pre-dam information is limited to historic reports and archival photographs. We conclude that multiple study approaches are essential to provide confident interpretations of ecological impacts downstream from dams, and propose a comprehensive study for Hells Canyon that integrates multiple research strategies.     

External threats: the dilemma of resource management on the Colorado River in Grand Canyon National park,USA

The United States Congress established Grand Canyon National Park in 1919 to preserve for posterity the outstanding natural attributes of the canyon cut by the Colorado River. In some cases National Park Service attempts to maintain Grand Canyon's natural environment have been thwarted by activities outside the park. One of the most obvious external threats is Glen Canyon Dam, only 26 km upstream from the park boundary. Constructed in 1963, this gigantic dam has greatly altered the physicochemical and biological characteristics of 446 km of the Colorado River in Grand Canyon National Park. The river's aquatic ecosystem has been greatly modified through the loss of indigenous species and the addition of numerous exotics. We consider this anexotic ecosystem. The riparian ecosystem has been less modified, with addition of a few exotics and no loss of natives—this we consider anaturalized ecosystem.The great dilemma now faced by park managers is that, after 20 years of managing resources along a river controlled by Glen Canyon Dam, the Bureau of Reclamation has proposed major changes in operational procedures for the dam. Scientists and managers from the National Park Service, Bureau of Reclamation, and cooperating federal and state resource management agencies are using a systems analysis approach to examine the impacts of various Colorado River flow regimes on aquatic, riparian, and recreational parameters in the park. This approach will help in the development of management alternatives designed to permit the most efficient use of that river's natural resources without their destruction.     

Twenty Years of Change on Campsites in the Backcountry of Grand Canyon National Park

This article draws on three separate research and monitoring studies to describe 20-year trends in the number and condition of campsites in the backcountry of Grand Canyon National Park. Results are used to assess the effectiveness of a complex and innovative management program, adopted in 1983, that sought to concentrate use on designated campsites in popular places and disperse camping in more remote places. In 1984, conditions on 12 high-use campsites and 12 low-use campsites were carefully assessed. Conditions on 22 of these campsites were reassessed in 2005. In addition, campsite-monitoring surveys were conducted between 1985 and 1992 and again in 2003 and 2004. In these surveys, all campsites were located and their condition rapidly assessed. The detailed assessment of a sample of sites suggests relatively little change in condition during the 20-year period. The high-use sites were more highly disturbed than the low-use sites, but they did not change more during the study period. In contrast, changes at larger scales were dramatic. The total number of campsites more than doubled during the study period. Surprisingly, the proliferation of new campsites was greater in places where camping was only allowed on designated campsites than in places where camping was allowed anywhere. Concern that concentration of use on designated sites would cause unacceptable impact was unfounded. Management implications for other internationally significant protected areas that allow backcountry camping are explored.     

Models,Assumptions, and Stakeholders: Planning for Water Supply Variability in the Colorado River Basin1

Abstract: Declining reservoir storage has raised the specter of the first water shortage on the Lower Colorado River since the completion of Glen Canyon and Hoover Dams. This focusing event spurred modeling efforts to frame alternatives for managing the reservoir system during prolonged droughts. This paper addresses the management challenges that arise when using modeling tools to manage water scarcity under variable hydroclimatology, shifting use patterns, and institutional complexity. Assumptions specified in modeling simulations are an integral feature of public processes. The policymaking and management implications of assumptions are examined by analyzing four interacting sources of physical and institutional uncertainty: inflow (runoff), depletion (water use), operating rules, and initial reservoir conditions. A review of planning documents and model reports generated during two recent processes to plan for surplus and shortage in the Colorado River demonstrates that modeling tools become useful to stakeholders by clarifying the impacts of modeling assumptions at several temporal and spatial scales. A high reservoir storage‐to‐runoff ratio elevates the importance of assumptions regarding initial reservoir conditions over the three‐year outlook used to assess the likelihood of reaching surplus and shortage triggers. An ensemble of initial condition predictions can provide more robust initial conditions estimates. This paper concludes that water managers require model outputs that encompass a full range of future potential outcomes, including best and worst cases. Further research into methods of representing and communicating about hydrologic and institutional uncertainty in model outputs will help water managers and other stakeholders to assess tradeoffs when planning for water supply variability.     

Reconstructions of Soil Moisture for the Upper Colorado River Basin Using Tree‐Ring Chronologies1

Anderson, SallyRose, Glenn Tootle, and Henri Grissino‐Mayer, 2012. Reconstructions of Soil Moisture for the Upper Colorado River Basin Using Tree‐Ring Chronologies. Journal of the American Water Resources Association (JAWRA) 48(4): 849‐858. DOI: 10.1111/j.1752‐1688.2012.00651.x Abstract: Soil moisture is an important factor in the global hydrologic cycle, but existing reconstructions of historic soil moisture are limited. We used tree‐ring chronologies to reconstruct annual soil moisture in the Upper Colorado River Basin (UCRB). Gridded soil moisture data were spatially regionalized using principal components analysis and k‐nearest neighbor techniques. We correlated moisture sensitive tree‐ring chronologies in and adjacent to the UCRB with regional soil moisture and tested the relationships for temporal stability. Chronologies that were positively correlated and stable for the calibration period were retained. We used stepwise linear regression to identify the best predictor combinations for each soil moisture region. The regressions explained 42‐78% of the variability in soil moisture data. We performed reconstructions for individual soil moisture grid cells to enhance understanding of the disparity in reconstructive skill across the regions. Reconstructions that used chronologies based on ponderosa pines (Pinus ponderosa) and pinyon pines (Pinus edulis) explained more variance in the datasets. Reconstructed soil moisture data was standardized and compared with standardized reconstructed streamflow and snow water equivalent data from the same region. Soil moisture and other hydrologic variables were highly correlated, indicating reconstructions of soil moisture in the UCRB using tree‐ring chronologies successfully represent hydrologic trends.     

Evaluation of the Temporal Transferability of a Model Describing Dissolved Solids in Streams of the Upper Colorado River Basin1

Kenney, Terry A. and Susan G. Buto, 2012. Evaluation of the Temporal Transferability of a Model Describing Dissolved Solids in Streams of the Upper Colorado River Basin. Journal of the American Water Resources Association (JAWRA) 48(5): 1041‐1053. DOI: 10.1111/j.1752‐1688.2012.00667.x Abstract: The application of a nonlinear least‐squares regression model describing the sources and transport of dissolved solids in streams of the Upper Colorado River Basin, and that was calibrated using data from water year 1991, was evaluated for use in predicting annual dissolved‐solids loads for the years 1974 through 1998. Simulations for each water year were run using annual climate data. To evaluate how well the model captures the observed annual variability across the basin, differences in predicted annual dissolved‐solids loads for each simulated year and 1991 were compared with differences in monitored annual loads. The temporal trend of the differences between predicted annual loads for the simulated years and the load for 1991 generally followed the trend of the monitored loads. The model appears to underpredict the largest annual loads and overpredict some of the smaller annual loads. An underprediction bias for wetter years was evident in the residuals as was an overprediction bias, to a lesser degree, for drier years. A regression analysis on the residuals suggests that the underprediction bias is associated with precipitation differences from 1991 and with previously defined downward trends in dissolved‐solids concentrations in the basin. In general, given the representative climatic conditions, the model adequately performs throughout the period examined. However, the model is most transferable to years with climatic conditions similar to 1991.     

Environmental management of the stone cutting industry

Environmental Management of the stone cutting industry in Hebron is required to reduce the industry's adverse impact on the downstream agricultural land and the adverse impact on the drinking water aquifers. This situation requires the implementation of an industrial wastewater management strategic approach and technology, within the available technical and financial resources. Ten pilot projects at different locations were built at Hebron to reduce or eliminate the incompatible discharge of the liquid and solid waste to the environment and improve the stone cutting industry's effluent quality. A review of existing practices and jar test experiments were used to optimize the water recycling and treatment facilities. The factors reviewed included influent pumping rates and cycles, selection of the optimal coagulant type and addition methods, control of the sludge recycling process, control over flow rates, control locations of influent and effluent, and sludge depth. Based on the optimized doses and Turbidity results, it was determined that the use of Fokland polymer with an optimal dose of 1.5mg/L could achieve the target turbidity levels. The completion of the pilot projects resulted in the elimination of stone cutting waste discharges and an improvement in the recycled effluent quality of 44-99%. This in turn reduced the long term operating costs for each participating firm. A full-scale project that includes all the stone cutting firms in Hebron industrial area is required.     

岷江上游水电开发对环境的影响

岷江上游水力资源十分丰富,随着西部大开发的进行,它已成为水电开发的重点区域,干流及支流的电站建设加速进行。自源头至汶川上游河段,实行六级梯级开发方案。但由于岷江水电工程主要是涵洞引水式,原来奔腾的河流变成了地下暗流,使得岷江的多处河段变得干涸,河谷的自然生境和景观发生了很大的变化,原来的干旱河谷气候变得更加干旱。也使河流生物系统受到严重影响。作者在对长江上游考察的基础上对岷江上游水电开发现状及其对环境的影响进行了分析,提出应该进行流域统一规划,强化执法监督,水电开发与环境保护建设并重;加强上中下游统一管理,注重流域综合开发等建议。     

Colorado River Floods, Droughts, and Shrimp Fishing in the Upper Gulf of California, Mexico

Accurate procedures that measure hydrologic variability would have great value for evaluating ecosystem impacts of upstream water use in the Colorado River Basin. Many local extractive income-based stakeholders rely directly or indirectly on ecosystem health and are adversely affected when the river does not flow. This study focuses on the impact of little or no Colorado River flow on the Mexican shrimp industry. Although there have been complaints that U.S. diversions of Colorado River flow have greatly impaired the shrimp fishery, this research demonstrates that freshwater rarely reaches the Gulf even during times of flooding, and that other factors such as overfishing may influence the instability of shrimp populations. Advanced very-high-resolution radiometer (AVHRR) satellite imagery was used to assess water volumes diverted away from the channel of the Colorado River and ultimately the Gulf of California during flooding periods. Analysis of data demonstrated that little freshwater actually reaches the Gulf even during floods because of its diversion into a large dry lake bed basin known as Laguna Salada. Fuller use of the Colorado River throughout its entire course to the sea is possible and could benefit a large cohort of users without catastrophic habitat destruction in delta ecosystems. Reconstruction of a natural earthen berm, as proposed by Ducks Unlimited, would maximize the use of floodwaters for ecosystem benefits. These findings have profound implications for local economic activities dependent on hydrologic resources in the Colorado River Delta and Upper Gulf.     

Stream macroinvertebrate baseline surveys: A comparative analysis from the oil-shale regions of Colorado,USA

General surveys of the benthic macroinvertebrates from Piceance Creek and the White River were conducted for nearly a decade prior to oil-shale exploitation in north central Colorado, USA. Comparison of the taxa collected in four studies on Piceance Creek and five studies on the White River shows little similarity among most studies. Studies were generally consistent in methods, site selection, and time of year for collection. Lack of agreement among the studies on what constitutes a baseline of common taxa is probably a result of taxonomic difficulties and differences in technique. More emphasis should be placed on testing possible impacts than on repeated, expensive, and inconclusive baseline inventories.     

Environmental audit: III. Improving the management of environmental information for toxic substances

Environmental programs have been commonly driven by a preoccupation with the collection of data in the mistaken belief thatdata is synonymous withinformation. The distinction between data (that is, the quantified and qualitative attributes of a particular environment) and information (specifically, data processed so as to focus upon a particular environmental problem) will become far more important to environmental managers. They will increasingly manage their information through use of what has become known as information resource management (IRM) and the attendant use of critical success factors methodology. Environmental managers will thereby move away from concerns about data and specific EDP hardware and applications toward managing information as a valuable agency resource. In applying IRM, they will find it helpful to include a number of planning elements and to resolve early a number of issues critical to its successful use.     

Ten Key Questions About the Management of Water in the Yellow River Basin

Water is scarce in many regions of the world, clean water is difficult to find in most developing countries, there are conflicts between irrigation needs and urban demands, and there is wide debate over appropriate means of resolving these problems. Similarly, in China, there is limited understanding of the ways in which people, groups, and institutions contribute to, are affected by, and respond to changes in water quantity and quality. We use the example of the Yellow River basin to argue that these social, managerial, and policy dimensions of the present water problems are significant and overshadow the physical ones. Despite this, they receive relatively little attention in the research agenda, particularly of the lead agencies in the management of the Yellow River basin. To this end, we ask ten research questions needed to address the policy needs of water management in the basin, split into two groups of five. The first five relate to the importance of water in this basin and the changes that have affected water problems and will continue to do so. The second five questions represent an attempt to explore possible solutions to these problems.     

Sedimentary Causes and Management of Two Principal Environmental Problems in the Lower Yellow River

Flood and water shortage are two of the leading environmental problems around the world, and among the causes of the problems is sedimentation. The Yellow River brought disastrous floods in its lower reaches in Chinese history. Today, although floods caused by the river are still a formidable hazard hanging over China, it cannot provide the lower reaches with enough usable water. The ineradicable flood hazard and newly emerged water shortage problems of the river are proved to be closely associated with its immense sediment load. The over loaded flow of the river can quickly fill the reservoirs and unceasingly raise the riverbed, attenuating the capacity of reservoirs to suppress floods and provide more water for dry seasons and of river channels to convey floods. Also, the high sediment content pollutes the water and reduces the volume of usable water. In virtue of the intimate linkage between these problems and the formidable sediment load in the river, the solution to these problems should be based on sedimentation management. After reviewing the defects and merits of management measures implemented and proposed, a management scenario composed of multiple measures are recommended. Beside of persistent soil conservation to reduce the huge sediment load, more reservoirs to check sediment and regulate river flows, approaches to alleviating riverbed accretion, interbasin water transfer to mitigate water deficiency, and so on, an emphasis should be laid on use of muddy flows in order to scatter the sediment in a vast area, which was a natural process but has been interrupted by construction of embankments.     

A historical perspective of river basin management in the Pearl River Delta of China

Three innovations in water and soil conservancy technology in the Pearl River Delta of South China, i.e., dike building, land reclamation, and dike-pond systems, were examined from a historical perspective. They were found to best reflect local farmers' efforts to cope with the challenges of various water disasters and to build a harmonious relationship with the changed environment. These technologies were critical to the agricultural success and sustainability over the past 2000 years, and reflected local farmers' wisdom in balancing land use and environmental conservation. Imprudent use of a new agricultural technology could damage the environment, and could disturb the human-environment relationship, as evidenced by the more frequent flooding that followed inappropriate dike building and premature reclamation. It is suggested that as the urbanization and industrialization process in the delta region continues, the kind of thinking that made the water and soil conservancy sustainable needs to be incorporated into the design of similar technologies for water use and river basin management today.