COOPERATIVE MANAGEMENT OF THE DUNGENESS WATERSHED TO PROTECT SALMON IN WASHINGTON STATE1

ABSTRACT: Over the last decade, the Jamestown S'Klallam Tribe has formed partnerships with their neighboring county government, irrigation districts, property owners, and state and federal agencies in an effort to save the dwindling runs of Dungeness River salmon. Although considerable progress has been made to begin the recovery process, the watershed is included in recent listings of Pacific Northwest salmon under the Endangered Species Act. Under the coordination of an active watershed council, significant improvements have been made in water conservation and the protection of instream flows. Cooperation between the Tribe, irrigation districts and the Washington Department of Ecology resulted in a trust water rights agreement and the reduction of late summer water withdrawals by one‐third.     

EXPORT COEFFICIENT MODELING TO ASSESS PHOSPHORUS LOADING IN AN URBAN WATERSHED1

ABSTRACT: An export coefficient modeling approach was used to assess the influence of land use on phosphorus loading to a Southern Ontario stream. A model was constructed for the 1995–1996 water year and calibrated within ± 3 percent of the observed mean concentration of total phosphorus. It was found that runoff from urban areas contributed most to the loading of phosphorus to the stream. When the model was assessed by running it for the 1977–1978 water year, using water quality and land use data collected independently, agreement within ± 7 percent was obtained. The model was then used to forecast the impact of future urban development proposed for the watershed, in terms of phosphorus loading, and to evaluate the reduction in loading resulting from several urban best management practices (BMP). It was determined that phosphorus removal will have to be applied to all the urban runoff from the watershed to appreciably reduce stream phosphorus concentration. Of the BMP designs assessed, an infiltration pond system resulted in the greatest phosphorus load reduction, 50 percent from the 1995–1996 baseline.     

SELECTION OF APPROPRIATE EVAPORATION ESTIMATION TECHNIQUE FOR CONTINUOUS MODELING1

ABSTRACT: The importance of evaporation in hydrologic modeling has been investigated by analysis of water budget at various scales and application of a water management model at plot scale. The data at all scales indicate that evaporation constitutes a major hydrological output. Accurate determination of watershed evapotranspiration depends upon appropriate accounting for the various components of evapotranspiration and their areal and temporal variability. An application of a water management model has revealed that the ranking of the sensitivity of input parameters depends upon the method of determination of evapotranspiration.     

Multiple attribute evaluation of landscape management

Economic approaches to the valuation of ecological services have several limitations. Some of these limitations can be overcome using the multiple attribute decision-making model developed in this paper. The model postulates that a private or public decision-maker selects a site/landscape management plan based on the biophysical and economic attributes of alternative management plans, the decision-maker’s preferences for attributes, and constraints on the selection of a management plan.Two cases are examined. Case A is a watershed consisting of publicly owned land that is managed at the site, management unit and landscape scales. Management is based on the philosophy of ecosystem management. Case B is a watershed composed of several privately owned units that are managed at the site scale by decision-makers whose primary motivation is economic profit. The preferred management plan in both cases is determined using a two-stage procedure. The first stage uses a stochastic programming model to identify the most efficient management plans for a site/landscape. The second stage determines which efficient management plan for a site/landscape is preferred by maximizing an expected utility function that is additive in the attributes and assumes that the decision-maker is risk neutral.Whether a land-management plan results in strongly or weakly sustainable resource conditions is evaluated. Strong sustainability requires the probability of exceeding the minimum acceptable value of an attribute to be greater than or equal to a pre-determined reliability level for each attribute. Weak sustainability requires the same condition except that it applies to a composite index of the attributes rather than each attribute. Bayes theorem is used to evaluate uncertainty about whether the state of a landscape is sustainable.     

基于能值拓展的流域生态外溢价值补偿研究——以渭河流域上游为例

流域上、下游间环境保护成本和收益的区域错配问题严重影响我国流域整体发展的公平与效率,下游地区对上游地区给予适当的经济补偿已成为解决流域区域间经济发展失衡、实现流域水资源可持续发展的重要手段。文章首先构建基于能值拓展的流域生态外溢价值计量模型,从能量投入和能级转化的角度,以能值的形式反映流域客观存在的社会、经济和生态的功能服务价值,利用能值分析法测算流域生态系统服务能值与水足迹法确定流域自身消费的生态能值,通过比较流域生态系统服务能值和流域生态能值自身消费情况,判断流域的生态盈亏状态,并进一步利用能值-货币比率将生态外溢能值转化为生态外溢价值,得到相对客观和稳健的补偿标准。然后以渭河流域上游为例,测算得到2013年渭河流域上游的生态外溢能值为1.16×1022sej,可知流域上游在扣除自身消费的生态能值后还为流域下游提供生态服务,处于生态盈余的状态。为激励上游地区加大流域生态环境保护力度,同时也为实现区域发展的公平与效率和流域水资源的可持续发展,下游地区应对上游地区支付水资源生态环境补偿,根据能值-货币比率得到上游应获得16.31亿元的补偿金额,并根据水资源可利用量进一步分配,得到定西市和天水市应分别获得7.50亿元和8.81亿元的补偿金额。基于该研究结果,建议通过扩大对流域上游地区的转移支付、完善水资源市场构建、健全流域生态补偿立法等政策提高上游地方政府的生态保护努力水平,优化水资源配置,实现流域整体的可持续发展。     

典型喀斯特流域地表产流输出特征

由于喀斯特区域表层岩溶带的结构和构造表现为高度的异质性,以及大量缺失定位观测资料,使得该区域目前还没有较为完善的产汇流模型。对特定小流域地表产流输出过程的分析,有利于对流域内部各种水文过程的认识。本研究正是基于这一背景,通过对一完整自然年的地表产流输出进行分析发现,流域地表径流输出主要发生在5~10月份;受雨强和壤中流向地表径流转化过程的影响,5月份的地表径流产流输出为突发衰弱型伴有明显的迟滞效应,其他月份主要为渐进增强衰弱型,迟滞效应较5月份明显减弱;如去除5月份的影响,6~10月份流域地表径流输出量与降雨量呈显著正相关关系(p0.05,r=0.99);壤中流向地表径流径流转化具有明显的季节性差异;就全年而言,经由卡口站地表径流输出的量占全年降雨总量的23.1%。     

Nitrogen Subsidies from Hillslope Alder Stands to Streamside Wetlands and Headwater Streams,Kenai Peninsula,Alaska

We examined nitrogen transport and wetland primary production along hydrologic flow paths that link nitrogen‐fixing alder (Alnus spp.) stands to downslope wetlands and streams in the Kenai Lowlands, Alaska. We expected that nitrate concentrations in surface water and groundwater would be higher on flow paths below alder. We further expected that nitrate concentrations would be higher in surface water and groundwater at the base of short flow paths with alder and that streamside wetlands at the base of alder‐near flow paths would be less nitrogen limited than wetlands at the base of long flow paths with alder. Our results showed that groundwater nitrate‐N concentrations were significantly higher at alder‐near sites than at no‐alder sites, but did not differ significantly between alder‐far sites and no‐alder sites or between alder‐far sites and alder‐near sites. A survey of ¹⁵N stable isotope signatures in soils and foliage in alder‐near and no‐alder flow paths indicated the alder‐derived nitrogen evident in soils below alder is quickly integrated downslope. Additionally, there was a significant difference in the relative increase in plant biomass after nitrogen fertilization, with the greatest increase occurring in the no‐alder sites. This study demonstrates that streamside wetlands and streams are connected to the surrounding landscapes through hydrologic flow paths, and flow paths with alder stands are potential “hot spots” for nitrogen subsidies at the hillslope scale.     

基于“三生共赢”的小流域水环境综合治理对策研究

小流域是实现重点流域精准化治理的基本单元,"三生共赢"是指要把解决环境问题的目标定位于生活、生产与生态的协调发展,是实现小流域环境改善和可持续发展的根本路径。本研究立足于流域水环境质量改善,以"三生共赢"和可持续发展理念为指导,提出了基于"三生共赢"的小流域水环境综合治理理论架构,即立足于水环境质量改善和水资源的优化配置,强化流域水环境约束,以尽可能小的环境代价支撑流域经济结构优化、新型城镇化发展,以资源高效和循环利用为核心,大力发展循环经济体系和循环社会体系,并通过创新流域治理体制机制构建成本共担利益共享格局,最终实现小流域社会经济可持续发展。本研究基于以上理论架构设计了生态环境、绿色经济、优质宜居三大类指标体系24项具体指标,并重点从优化流域空间开发格局、构建产业绿色发展体系、改善城乡居民生活环境、提升流域生态系统功能、健全流域治理体制机制等方面分析了小流域水环境综合治理对策。本研究可为各级政府创新流域治理模式、制定小流域水环境综合治理规划提供较为可行的理论支撑和技术体系。     

Response of Nitrogen Loading to the Chesapeake Bay to Source Reduction and Land Use Change Scenarios: A SPARROW‐Informed Analysis

In response to concerns regarding the health of streams and receiving waters, the United States Environmental Protection Agency established a total maximum daily load for nitrogen in the Chesapeake Bay watershed for which practices must be in place by 2025 resulting in an expected 25% reduction in load from 2009 levels. The response of total nitrogen (TN) loads delivered to the Bay to nine source reduction and land use change scenarios was estimated using a Spatially Referenced Regression on Watershed Attributes model. The largest predicted reduction in TN load delivered to the Bay was associated with a scenario in which the mass of TN as fertilizer applied to agricultural lands was decreased. A 25% decrease in the mass of TN applied as fertilizer resulted in a predicted reduction in TN loading to the Bay of 11.3%, which was 2.5–5 times greater than the reductions predicted by other scenarios. Eliminating fertilizer application to all agricultural land in the watershed resulted in a predicted reduction in TN load to the Bay of 45%. It was estimated that an approximate 25% reduction in TN loading to the Bay could be achieved by eliminating fertilizer applied to the 7% of subwatersheds contributing the greatest fertilizer‐sourced TN loads to the Bay. These results indicate that management strategies aimed at decreasing loading from a small number of subwatersheds may be effective for reducing TN loads to the Bay, and similar analyses are possible in other watersheds.     

The U.S. Flood Control Program at 75: Environmental Issues1

Black, Peter E., 2012. The U.S. Flood Control Program at 75: Environmental Issues. Journal of the American Water Resources Association (JAWRA) 48(2): 244‐255. DOI: 10.1111/j.1752‐1688.2011.00609.x Abstract: Recent, recurring, and increased magnitude floods adversely challenge long‐held and erroneous concepts of flood control. This article focuses on the environmental issues with comprehensively reviewed essentials of the United States (U.S.) riverine Flood Control Program, including news reports, scientific articles, books, and landmark treatises. For the past three‐quarters of a century, U.S. floods have continued (and will continue) to occur, causing increasing property damage with growing fiscal loss. Reasons include inattention to fundamental principles of physics, hydrology, and ecology. There are also important challenges involving environmental policy, economics, and common sense. Measures afforded by the existing program encourage and enable investment in floodplains while violating a variety of natural principles that make the situation worse. This detailed review includes the questionable (actually untrue) justification in the document‐setting policy for the 1936 Omnibus Flood Control Act. The well‐documented evidence is overwhelming. An alternative approach is presented that would enable and celebrate natural floods, managing their ecological and hydrological values, and not attempting to control them.