Spatially Explicit Modeling of Land Use Specific Phosphorus Transport Pathways to Improve TMDL Load Estimates and Implementation Planning

Diffuse pollution from urban stormwater and agricultural runoff are among the leading causes of water pollution in the USA. A process-oriented, stakeholder-driven research approach was implemented in the small heterogeneous watershed of St. Albans Bay, Vermont to model the relative load of phosphorus from all sources, including diffuse transport pathways, and compared to goals and assumptions outlined by a Total Maximum Daily Load (TMDL) developed for phosphorus in Lake Champlain. Mass-balance and dynamic landscape simulation models were used to describe the distribution of the average annual phosphorus load to streams (10.57 t/year) in terms of space, time, and transport process. The majority of the phosphorus load comes from two subwatersheds dominated by clay soils, Stevens and Jewett Brooks. Dissolved phosphorus in surface runoff from the agricultural landscape, driven by high soil phosphorus concentrations, accounts for 41% of the total load to watershed streams. Direct discharge from farmsteads and stormwater loads, primarily from road sand wash-off, are also significant sources. Results reported in this study could help target watershed interventions both in terms of the types and locations of recommended best management practices (BMPs). The study offers an approach to attaining TMDL diffuse pollution targets in a cost-effective and participatory manner and could be replicated for other TMDL processes around the country.     

韩江流域面源污染及与景观格局的关系

为了定量研究韩江流域的面源污染情况以及景观格局对污染的影响,建立了流域水文水质模型,并采用多元线性回归、冗余分析方法,探索景观指标与污染物质量浓度变化量的关系。结果表明:西部宁江流域地区的总氮质量浓度较高,最大值为3.91 mg/L;东部汀江流域地区总磷质量浓度较高,最大值为2.15 mg/L;流域总体水质呈恶化趋势;景观指标能解释81.7%的面源污染变化,且景观的面积越大,其组成格局可能比空间格局对水质的影响更大;林地的面积百分比与面源污染负相关,农田、城镇、草地景观则相反;城镇或农田等人类景观的斑块密度、形状指数等空间格局指标与污染物质量浓度负相关;旱地相比水田对面源污染的贡献更大;在研究区采用退草还林、农业结构调整等管理措施分别能够削减1.82%和4.63%的总氮负荷以及1.16%和7.31%的总磷负荷。     

城市水管理与海绵城市建设之理论基础—城市水文学研究进展

过去数十年来,我国经济社会快速发展,城市化进程不断加快,但由于不合理的城市规划和建设,自然水循环系统受到无序的干扰和破坏,引发了一系列城市水问题,城市水管理工作面临巨大挑战。城市水管理的理论支撑就是以研究城市水循环为核心的城市水文科学,"海绵城市"建设作为我国现代城市水管理的重大战略,必须以城市水文学理论为依据,深入研究城市水循环机理和规律。本文围绕城市水管理支撑理论,系统梳理了国内外在城市化水文效应、城市产汇流理论、城市雨洪模拟与管理方面的研究进展,指出城市水文观测与预报、城市化水文效应与产汇流理论、城市综合水系统模型研究是当前和未来一段时间研究的重点和难点。提出了我国当前城市水管理和海绵城市建设所面临的城市产汇流基础理论、城市气象水文监测和水文过程模拟技术问题,以及城市水文学研究应对变化环境下城市复杂的综合水问题开展基于多学科理论的全面精细化模拟分析的基本思路。     

Sustainable Urban Water System Transitions Through Management Reforms in Ghana

Despite decades of water reforms, Ghana’s struggle to achieve sustainable urban water system is deepened by complex interactions of multi-layered political, socio-economic and managerial characteristics, leaving a rationing system of water supply in major cities like Accra. Using a multi-level perspective framework, the paper examines the dynamics of urban water system transition through management reforms. The study showed how external pressure at the landscape level influenced policy direction within urban water regime through the implementation of neo-liberal economic policies, paving way for resistance and grassroots innovation at the niche level. The implementation of such policies in the reform process did little to help achieve the desired sustainable urban water system goals. The paper suggests a blend of public and private financing with support for grassroots to improve urban water system management. However, subsequent urban water policy reforms must be informed by knowledge of social, economic, and political realities rather than imported generic “best policies and practices” that often conflict with local realities.     

城市降雨径流污染初始冲刷效应对BMPs选择的启示

指出城市降雨径流污染初始冲刷效应(FFE)在城市非点源污染的研究中占有重要地位。综述FFE的判定及大小定量化方法、季节性FFE的概念和污染物的相态对FFE的影响。FFE初中期雨水径流污染物浓度高的特性,为选择经济高效的最佳管理措施(BMPs)提供了理论依据和重要启示。结合FFE及冲刷过程中污染物的形态提出的工程BMPs,能使资源配置和污染控制效果达到最优化,为城市公共管理部门的决策和实践提供建议。     

Integrated urban stormwater management: Evolution and multidisciplinary perspective

This paper proposes an introductory review of the historical evolution of urban stormwater management, as well as of current trends, challenges, and changes of paradigm. It reminds us first that most of the existing urban stormwater infrastructures in developed cities are based on the modern urban sewer systems developed in the second half of the 19^th century in Europe. They have been built and for decades managed almost solely by urban sanitation and water specialists, relatively independently of other technical services and, more generally, of other stakeholders in cities. They contributed significantly to public health and fast conveyance of stormwater outside the cities. However, at the turn of the 1970s, it became evident with increasing urbanisation that they also had drawbacks: artificialisation of soils, reduction of aquifer recharge, pollution of surface water and ecological impacts, etc. The paper indicates how new concepts and paradigms thereafter emerged to manage stormwater by means of more sustainable and integrated approaches, aiming to solve the problems engendered by the previous approaches. This integration embraces more and more disciplines and issues, far beyond the traditional field of urban water engineers and specialists. The paper attempts to explain the need for this evolution, making urban stormwater management more much complex, dealing and interacting with ecology, biodiversity, bioinspiration, architecture, landscape and water values, citizens’ well-being, history, culture, and socio-economic aspects.     

绍兴市环城河水污染现状与对策研究

绍兴市环城河水质现状已不容乐观，造成水质污染的主要原因：一是城市生活产生的污（废）水，二是上游工业污（废）水，三是上游农村面源污染和生活污染，四是上游渔业养殖污染。在客观分析水体污染原因的基础上，结合区域实际，有针对性地采取截流、控源、治污和活水等综合措施，提出了解决的办法与对策。     

An Integrated Approach for Targeting Critical Source Areas to Control Nonpoint Source Pollution in Watersheds

This study presents an integrated approach for targeting critical source areas (CSAs) to control nonpoint source pollution in watersheds. CSAs are the intersections between hydrologically sensitive areas (HSAs) and high pollution producing areas of watersheds. HSAs are the areas with high hydrological sensitivity and potential for generating runoff. They were based on a soil topographic index in consistence of a saturation excess runoff process. High pollution producing areas are the areas that have a high potential for generating pollutants. Such areas were based on simulated pollution loads to streams by the Soil and Water Assessment Tool. The integrated approach is applied to the Neshanic River watershed, a suburban watershed with mixed land uses in New Jersey in the U.S. Results show that several land uses result in water pollution: agricultural land causes sediment, nitrogen and phosphorus pollution; wetlands cause sediment and phosphorus pollution; and urban lands cause nitrogen and phosphorus pollution. The primary CSAs are agricultural lands for all three pollutants, urban lands for nitrogen and phosphorus, and wetlands for sediment and phosphorus. Some pollution producing areas were not classified into CSAs because they are not located in HSAs and the pollutants generated in those areas are less likely to be transported by runoff into streams. The integrated approach identifies CSAs at a very fine scale, which is useful for targeting the implementation of best management practices for water quality improvement, and can be applied broadly in different watersheds to improve the economic efficiency of controlling nonpoint source pollution.     

海绵城市建设中若干水文学问题的研讨

针对海绵城市建设面临的问题和挑战,提出了以水循环为纽带、将城市暴雨-径流、水污染治理和城市生态绿地、湿地建设与市政建设(排水、排污)规划管理联系为一体的"城市水系统"的概念与方法。基于水文学原理,分析了目前海绵城市建设中最为关键、也是质疑较多的年径流总量控制率概念,指出现行的年径流总量控制率的计算实质是年降水总量控制率。如果回归到水文学概念,年径流总量控制率就必须与水文系统响应的增益因子,即径流系数建立内在的联系;需要研究径流系数并非常数,而是与土壤湿度、降水强度和下垫面组合的时变非线性理论问题。此外,对比分析了现行海绵城市建设低影响开发措施和改进后的年径流总量控制率之间的关系,深入剖析了"城市看海"发生的条件与风险。最后就海绵城市建设与规划的水文学基础亟待改进的方面:径流系数非线性、区分自然条件和城市化后的蓄水量变化的差别、考虑河湖水系调蓄和陆地蒸散发、与流域大海绵调控结合、风险管理等,进行了研讨,并提出了未来我国海绵城市建设的若干建议。     

Democratic Legitimacy of New Forms of Water Management in the Netherlands

Due to changes in the Dutch flood management paradigm, governance practices have been shifting from technocratic and state-oriented towards more collaborative governance approaches in which many governmental actors, together with private and societal actors, search out integral solutions. This shift has had an impact on how water management is legitimized. This paper evaluates two water governance processes that reflect the new management paradigm in different ways, and analyzes how these changing paradigms influence the democratic legitimacy of water governance. It is concluded that the extent to which the new paradigm is implemented influences the way in which democratic legitimacy is organized. It is also shown that new forms of democratic legitimacy do not replace existing ones but rather contribute to hybrid and contextualized forms of legitimacy.     

Climate change will both exacerbate and attenuate urbanization impacts on streamflow regimes in southern Willamette Valley,Oregon

Interactions between climate change and urbanization may affect stream ecosystems in unexpected ways. With an integrated modelling framework, we assessed the combined hydrological impacts of climate change and urbanization under historical and future climate regimes across varied development scenarios in three watersheds in the Willamette Valley, Oregon. First, through an agent‐based land use change model Envision, we created four development scenarios that consisted of 2 × 2 combinations of regional growth (compact population growth in urban cores vs. dispersed growth into rural areas) and stormwater management scenarios (with vs. without integrated stormwater management, ISM). ISM was defined as the integration of strategic organization of land uses with site‐scale stormwater best management practices. Next, two future climate regimes were developed by statistically downscaling projections from two general circulation models (CanESM2 and CNRM‐CM5) that performed well in replicating historical climate. The hydrological assessment of these scenarios was then conducted with the Soil and Water Assessment Tool. Using 10 ecologically significant flow metrics, we evaluated each scenario based on the magnitude of change in each metric and the degree to which such changes could be mitigated. Climate change alone led to a drying trend in flow regimes under both future climates. Combined with urbanization, it magnified changes in six of 10 metrics but attenuated impacts for three other measures of flashiness in at least one basin. The combination of compact growth and ISM effectively mitigated alterations for seven (out of nine) metrics sensitive to the combined impacts in at least one basin, with ISM being more effective than compact growth. The modelling framework teased out both nuanced differences and generalizable trends in hydrological impacts of urbanization and climate change and offers key methodological innovations towards an integrated framework capable of linking landscape planning mechanisms with the goal of sustaining stream ecosystem health.     

A Landscape Planning and Management Tool for Land and Water Resources Management: An Example Application in Northern Ethiopia

Land and water degradation due to on-site soil/nutrient loss and off-site pollution/sedimentation are serious environmental problems. Landscape planning and management tools are essential to implement best management practices targeted at locations where they are needed most. Although many soil/water-landscape studies have been published in the last 2 decades, progress in developing operational tools for supporting landscape planning to minimize land and water degradation in developing regions is still modest. Some of the existing tools are data demanding and/or complicated to be useful to data scarce regions. Some require detailed understanding of the hydrological and modelling processes and thus less applicable to local stakeholders involved in land use planning and management. A user-friendly LAndscape Planning and MAnagement Tool (LAPMAT) developed to facilitate land management decision-making. LAPMAT is a menu-oriented interactive graphical user interface that can aid decision makers identify hotspot areas of soil erosion and evaluate the effects of alternative land use management practices at a catchment scale. The modelling framework and its interfaces are designed to guide the user through a series of menus that: 1) allow input model parameters, adjusting coefficients, visualizing input parameters and executing the model; 2) enable changing land use and management practices and re-evaluating potential consequences; 3) allow viewing results in tabular, graphical or map form side-by-side; and 4) (re)-evaluating the respective impacts of management/conservation options. The framework has been applied to assess the severity of soil erosion and simulate the impact of different land management practices using the Revised Universal Soil Loss Equation (RUSLE) adjusted for sediment delivery ratio in an example catchment of northern Ethiopia. The results showed average sediment yield rate of 55 t ha^?1 y^?1. Conservation measures targeted at high soil loss areas and gullies gave the maximum reduction in sediment yield by about 80 %. Since LAPMAT allows users handle the selection of management/planning options and provide fast and responsive outputs, it can assist in effective multi-stakeholder negotiations over land-use planning where the minimization of land/water degradation is the ultimate goal.     

湟水干流西宁～民和段河道生态基流量研究

湟水是青海省地表水利用率最高的河流,湟水干流西宁~民和段也是青海省水污染最严重的河段之一。本文以乐都水文站和民和水文站断面为控制节点,利用实测水文资料,通过历史水文资料法,初步确定西宁~民和段河段生态基流量为4.55 m3/s。这将为湟水中下游水资源可持续利用的管理目标提供了现实途径,具有现实意义。     

Life cycle optimisation for highway best management practices.

Highway runoff can cause a number of water quantity and quality problems. Stormwater management systems for highways have been developed based on a fast drainage for large storm situations. Non-point source pollution from highway runoff is a growing water quality concern. Stormwater quality control needs to be integrated into highway drainage design and operation to reduce the stormwater impacts on the receiving water. A continuous simulation/optimisation model for analysing integrated highway best management practices (BMPs) is presented. This model can evaluate the life cycle performance of infiltration and/or storage oriented highway BMPs. It can be directly integrated with spreadsheet optimisation tools to find the least cost options for implementing BMPs throughout a specified life cycle.     

Diffuse pollution in Japan: issues and perspectives.

Many parts of Japan have experienced rapid urbanization and industrialization over the past 50 years. This trend resulted in severe water pollution in many urban areas. To address the pollution problems, several measures such as construction of sewerage systems and enactment of laws and regulations have been undertaken. Because of these measures, the water quality has been improved to some extent. However, many water quality concerns still remain and are attributed in part to diffuse pollution. In this paper, historical progress, present situation and future aspects of diffuse pollution problems in Japan are reviewed. It is noted that solving diffuse pollution problems will require a combination of several measures including application of conventional treatment technologies and natural purification systems, implementation of appropriate policy measures, and promotion of citizen participation.     

Social Science Training for Engineers—Experiences from the USA

ABSTRACT

This paper puts the accent on field measurements of the terms of the hydrological cycle, i.e., precipitation, evapotranspiration, run-off and infiltration, in order to evaluate the available water storage in surface reservoirs, in soils, in aquifers for short and long term planning.

Methodological and technological improvements illustrate in this paper not only the difficulties in obtaining reliable field hydrological data but also the fact that the behavioural knowledge of each term of the hydrological cycle is compulsory in order to determine the limits of the socio-economic development which depends upon the quantity of water resources available and in order to prevent eventual irreversible degradation of the environment.

No universal model exists because a model depends not only on the meteorological, hydrological andgeological conditions of the area under study but also on the planner's objectives concerning urban, industrial, navigational, agricultural and/or recreational activities. The studies of water resources are, therefore, in a permanent stage of pre-management. This is due to the fact that they have to be constantly adapted to new management conditions.

This becomes more and more imperative since water resources studies have been, and still are, undertaken too often in order to solve specific and isolated problems arising from short-sighted and/or short term planning and management.     

城乡水务一体化管理的制度分析

本文分析了我国自20世纪末以来由于经济和社会变化产生的水问题,即包括城市化进程不断加快所导致的城市用水量的不断增加,以及城乡之间水事关系的日益密切;然后从制度的角度分析了水管理模式的改革,即要求改变过去的层级分解一信息包裹模式,建立一定的协调机制或合并有关机构;最后指出在实施城乡水务一体化管理以后,仍然需要正确协调和处理水的资源管理、服务管制和环境管理之间的关系。     

Simultaneous estimation of model parameters and diffuse pollution sources for river water quality modeling.

Diffuse pollution sources along a stream reach are very difficult to both monitor and estimate. In this paper, a systematic method using an optimal estimation algorithm is presented for simultaneous estimation of diffuse pollution and model parameters in a stream water quality model. It was applied with the QUAL2E model to the South Han River in South Korea for optimal estimation of kinetic constants and diffuse loads along the river. Initial calibration results for kinetic constants selected from a sensitivity analysis reveal that diffuse source inputs for nitrogen and phosphorus are essential to satisfy the system mass balance. Diffuse loads for total nitrogen and total phosphorus were estimated by solving the expanded inverse problem. Comparison of kinetic constants estimated simultaneously with diffuse sources to those estimated without diffuse loads, suggests that diffuse sources must be included in the optimization not only for its own estimation but also for adequate estimation of the model parameters. Application of the optimization method to river water quality modeling is discussed in terms of the sensitivity coefficient matrix structure.     

Data- and model-driven determination of flow pathways in the Piako catchment,New Zealand

Quantifying flow pathways within a larger catchment can help improve diffuse pollution management strategies across subcatchments. But, spatial quantification of flow pathway contributions to catchment stream flow is very limited, since it is challenging to physically separate water from different paths and very expensive to measure, especially for larger areas. To overcome this problem, a novel, combined data and modelling approach was employed to partition stream flow in the Piako catchment, New Zealand, which is a predominantly agricultural catchment with medium to high groundwater recharge potential. The approach comprised a digital filtering technique to separate baseflow from total stream flow, machine learning to predict a baseflow index (BFI) for all streams with Strahler 1st order and higher, and hydrological modelling to partition the flow into five flow components: surface runoff, interflow, tile drainage, shallow groundwater, and deep groundwater. The baseflow index scores corroborated the spatial distributions of the flow pathways modelled in 1st order catchments. Average depth to groundwater data matched well with BFI and Hydrological Predictions for the Environment (HYPE) modeled flow pathway partitioning results, with deeper water tables in areas of the catchment predicted to have greater baseflow or shallow and deep groundwater contributions to stream flow. Since direct quantification of flow pathways at catchment-scale is scarce, it is recommended to use soft data and expert knowledge to inform model parameterization and to constrain the model results. The approach developed here is applicable as a screening method in ungauged catchments.     

日本鹤见川流域综合治水历程的启示

针对快速城镇化进程中洪涝风险加剧的难题,介绍了日本鹤见川流域在城镇化面积从10％上升至85％的进程中,流域水文环境及洪水特性等方面的变化,以及该流域综合治水对策从河道整治扩展为流域面上的蓄滞排渗措施、土地利用规划以及洪水预警预报等方面的进展.结合我国目前高速发展的态势,从鹤见川流域综合治水的循序渐进、计划治水的成本效益以及依法治水的保障作用等方面,分析了鹤见川流域综合治水经验给我们的启示.