Ecological Base Flow Research Articles

Establishment of watershed ecological water requirements framework: A case study of the Lower Yellow River, China

It is of great practical significance to ensure ecological water requirements (EWRs) for the maintenance of river health and the sustainable development of human socioeconomics. How to scientifically determine the comprehensive EWRs and estimate the uncertainty of hydro-ecological tools performed in the process of conducting remains one of the most important yet most complicated issues. In this study, the ecological water requirements framework (EWRsF) of the Lower Yellow River (LYR), which considers instream ecological base flow, survival and reproduction of indicator fish species, equilibrium of erosion and siltation and ecological function of the estuary, was constructed by integrating hydrological, hydraulic and ecological habitat methods. The framework contains three crucial components - determination of instream EWRs and estuarine EWRs, uncertainty analysis of hydro-ecological tools. For instream ecological base flow, we proposed an improved Tennant method, which took into account both seasonality and sediment transport characteristics of the LYR, and could better reflect the actual hydrological regime. For the hydrological ecological response relationship of indicator fish species, we estimated the uncertainty of the model output of River2D to improve its credibility of the simulation results. The results demonstrated that: 1) Two-grade intra-annual monthly EWRs process of suitable and minimum for four instream sections and estuary area were obtained. The flood season (June–October) is the period with the largest proportion of intra-annual instream EWRs, whereas in estuary area, is the spawning period (April–July) of dominant species. 2) The uncertainty of HSI curves directly leads to the uncertainty of model output. Although the shape and position of the WUA curve can be uncertain, it does not affect the judgment of EWRs threshold. 3) The research results can provide scientific basis for water resource management decision-making in the LYR. Additionally, the ideas also have reference significance for similar basins.

Value composition and quantitative calculation of economic value produced by river ecological base flow

Abstract The definition of the economic value (EV) produced by river ecological base flow (REBF) is the role of REBF in avoiding river shrink or dry up and maintaining ecosystem health and natural process of river. Scientific and accurate establishment of quantitative method for calculating the EV produced by REBF is helpful for humans to understand the benefits of REBF protection directly and optimize the allocation of water resources by means of economics. Based on the characteristics of non-consumable and multi-values of REBF, we first identified its value composition by referring to the EV classification of river. Next, we established calculation methods for each sub-value using evaluation techniques of resources and environment economics. Finally, on the basis of calculation results of sub-values and the relationship of sub-values, we determined the maximum EV supported by each kind of water requirements of REBF, and summed up all independent parts to obtain the total EV. This method can remove repeated calculations in the process of assessing the EV produced by REBF. Our results indicated that the minimum total EV produced by REBF in the Shaanxi section of the Wei River was 4.54 billion yuan in 2017, which is close to previous studies. The new method developed here should provide a better theoretical support for quantitative research of the EV produced by REBF and scientific management of limited water resources coming from river.

Assessment and conservation strategies for endemic fish with drifting eggs threatened by the cascade barrier effect: A case study in the Yalong River, China

Concern over declining populations of fish with drifting eggs due to the barrier effect caused by dam construction has led to intense interest in their conservation and management. As a major regulatory method, the studies on replenishing ecological flow through dam operation have mainly focused on the spawning period of fish with demersal or sticky eggs, and the potential impacts of this phenomenon on the reproduction of species with drifting eggs are not fully understood. With the establishment of an ecological model and status indicators, we quantified the barrier effect on spawning and hatching of the drifting-egg species, Coreius guichenoti, a dramatically declining endemic species in the Yalong River, China, and proposed that ecological base flow (EBF) closely links spawning and hatching opportunities to fish habitat demands. The results implied that the impacts differed across periods, with negative effects on fish spawning, while the most evident impacts occurred during hatching. The unsatisfactory hydraulic conditions during the hatching period were the drivers that limited local recruitment. Analysis of conservation strategies indicated that compared with regulating mainstream dams alone, the coordinated conservation of mainstream tributary dams caused a high positive change in fish resource supplementation. Reducing the water level of the downstream dam and cooperatively increasing the discharge of the tributary cascade when the upstream dam released EBF during the spawning (231.66 m3/s) and hatching periods (315.00 m3/s) were offered as management recommendations to reduce the barrier effect and preserve fish resources. Collectively, dammed mountain rivers offer a cautionary tale for developing nations with hydropower development intents, suggesting that while spawning habitat protection should remain an important component in fisheries management strategies, it will be crucial to link conservation with management strategies that encompass other early life stages.

Assessment of indirect agricultural losses caused by river ecological base flow protection

In order to coordinate the relationship between ecological base flow guarantee and agricultural water use, and promote the development of ecological base flow guarantee and compensation, this paper established an evaluation system of indirect agricultural losses caused by ecological base flow guarantee. Taking the Baojixia irrigation area as an example, the substitution method was used with the social security value of urban residents as a reference, and the coefficient in combination with the income ratio of urban and rural residents was modified to obtain the social security value of rural residents’ cultivated land, then the agricultural irrigation before and after the ecological base flow guarantee was combined. The amount of water diversion was changed, finally the indirect agricultural loss caused by the protection of ecological base flow was calculated. The results show that the upper and lower limits of total agricultural indirect losses in a typical year are 420 million yuan and 122 million yuan, respectively. Actually, since the Baoji Gorge Irrigation District undertakes the task of food supply in the Guanzhong area and even in Shaanxi Province, it is necessary to consider other factors such as food security when implementing the policy of guaranteeing the base flow.

A Bayesian network approach for determining optimal ecological base flow of rivers in water shortage areas of Northwest China.

How to balance natural river base flow with water loss from agricultural activities such as irrigation has become an important global challenge in areas of water shortage. Using a Bayesian network model, we constructed a decision-making framework for river ecological base flow in the water shortage areas. This framework can be divided into three components: (1) calculation of economic losses caused when priority is given to protect river ecological base flow, (2) construction of a decision-making Bayesian network, and (3) determination of an optimum ecological base flow of rivers based on an acceptable probability of acceptable economic losses the decision-makers selected. We used the Baoji section of the Weihe River as a typical water shortage area case study. The results show that the optimum ecological base flows in the Baoji section of Weihe River in wet, normal, and dry years were 32.35%, 20.59%, and 14.71% of natural inflow in rivers, respectively. From an economic benefit perspective, the beneficiaries should provide more financial support to protect the ecological base flow of rivers. Our approach could be used in other water shortage areas where decisions need to be made between protection of river ecological base flows of rivers and agricultural use.

Research on the exploitation and utilization degree of mineral water based on ecological base flow in the Changbai Mountain basalt area, northeast China.

Mineral water from the Changbai Mountain basalt area is China's most important source of drinking water. Mineral water with abundant output and enriched trace elements has driven the rapid development of the local economy. However, the extensive exploitation of mineral water and the neglect of ecological base flows threaten interdependent river ecosystems. In order to ensure the sustainable use of mineral water, it's necessary to calculate the exploitation and utilization of mineral water according to the ecological base flow. In this study, four hydrological methods were used to analyze the intra-annual and inter-annual ecological base flows, namely the Tennant method, the base flow ratio method, the driest monthly average flow method and the Texas method. The results show that the ecological base flow during the flood season is about 3-4 times that during the non-flood season. Affected by rainfall and runoff, the inter-annual ecological base flow also fluctuated within a small range. This study divides the mineral water exploitation coefficient into five categories and proposes an assessment of the mineral water exploitation potential based on the ecological base flow. It shows that the flow of Baijiang River spring group is the largest, but it's exploitation potential is normal. Huangni River spring group at weak level for exploitation because of its small flow rate. It's obvious that river runoff is not the only factor that determines the exploitation coefficient of the spring group. The proportion of ecological base flow and the proportion of river base flow are also important factors.

Improving water saving measures is the necessary way to protect the ecological base flow of rivers in water shortage areas of Northwest China

Low efficiency of water use in agricultural irrigation is the main obstacle preventing river ecological base flow protection in water shortage areas in Northwest China. By constructing a quantitative calculation model, the important contribution agricultural irrigation water-saving measures have on river ecological base flow protection are quantitatively analyzed in this study. Firstly, we determine water demand of the river ecological base flow combined with the river protection goal, determining water shortage in non-flood seasons combined with residual water in rivers after irrigation diversion. Secondly, we quantitatively determine water saving by combining water saving measures. Finally, we use water balance analysis to quantitatively calculate the protection degree and the protection rate of the river ecological base flow. Calculation results indicate that river ecological base flow from October to May of the next year is [5.66, 7.42 m3/s] and is greater than or equal to 21.69 m3/s from June to September. Total water saving after improving water saving measures are 66.55, 133.11 and 205.66 million m3 under three proposed scenarios; protection degree and protection rate after improving water saving measures in non-flood seasons under the three scenarios are 59.38%, 93.66% and 100%, and 45.92%, 74.02% and 100%, respectively, which gradually reached the target protection rate of 90% for river ecological base flow required by administrative departments. Comparison of advantages, disadvantages and costs of the three main protection modes indicated that improving water saving measures are the most reasonable protection measure to protect the ecological base flow of rivers. By using a quantitative study, a basis for reasonable safeguard measures of the ecological base flow of rivers in water shortage areas of Northwest China are presented.

Linking bait and feeding opportunities to fish foraging habitat for the assessment of environmental flows and river restoration

The survival of aquatic biota in different life history stages depends on food availability, water quantity and specific hydrological conditions, and is particularly susceptible in degraded rivers due to the development of hydropower or are sensitive to climate change. Habitats with limited food availability and restricted feeding opportunities can strongly affect the habitat carrying capacity and fish growth with consequences for spawning. Few environmental flow regime frameworks are available that closely link bait and feeding opportunities to fish foraging habitat. In addition, river restoration has been widely implemented to resolve the conflict between ecological demand and power generation benefits. Nevertheless, whether in-stream structures are still suitable for the joint operation of foraging and spawning habitats remains unclear. In this study, a framework to integrate the requirements of both spawning and foraging habitats into environmental flow regime assessments was proposed by coupling the bait supply, fish spawning and fish feeding opportunities. Here, we used the Batang Reservoir, located in the Tibetan Plateau, as an example to determine the environmental flow regimes. The environmental flow regimes during Periods I, II and III for the conservation of the life history stages of Schizothorax dolichonem were determined, which provided high-quality food and was beneficial for increasing the probability of restoration success. After the implementation of measures, the ecological base flow rate decreased from 171.80 m3/s, 206.00 m3/s and 257.70 m3/s to 138.00 m3/s, 206.00 m3/s and 206.00 m3/s in Periods I, II and III, respectively. We concluded that traditional river restoration with the use of in-stream structures is still suitable for the joint operation of spawning and foraging habitats, but the design selection and placement of in-stream structures should be preoptimized. The framework proposed will help managers evaluate habitat conservation to protect degraded rivers or help develop strategies to build resilience to climate change.

新疆白杨河流域特征及生态植被需水分析

PDF HTML阅读 XML下载 导出引用 引用提醒 新疆白杨河流域特征及生态植被需水分析 DOI: 10.5846/stxb201911092362 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 新疆水利科技专项（YF2020-01） Analysis on characteristics of Baiyang River Basin and water requirement of ecological vegetation in Xinjiang Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:新疆白杨河流域地跨上游乌鲁木齐市达坂城及下游吐鲁番市托克逊县两个行政区，上游达坂城区位于天山博格达峰山前冲击、洪积山间盆地干旱区，源于天山多支源流汇集于盆地南端峡口，基于峡口形成下游并由有多支流沿程补给白杨河干流，穿越极端干旱戈壁荒漠区的托克逊县直至末端吐鲁番市境内尾闾-艾丁湖，是我国典型少有的跨越干旱与极端干旱叠加型流域灌区，水资源有效利用及水生态环境保护具有重要作用。遵循流域各河流水系形成的自然生态环境属性及河道取水工程节点，采用Penman-Monteith法生态需水定额和卫星遥感面积识别及水文年内展布方法，分析评估流域内上下游绿洲生态环境植被需水量和河流生态基流及其调控断面。结果表明，上游达坂城区黑沟河年生态需水量、生态基流、年均径流占比和控制断面，分别为921万m3、0.29m3/s、18%和黑沟渠首；阿克苏河为1048万m3、0.33m3/s、12%和阿克苏渠首；高崖子河为862万m3、0.27m3/s、12%和高崖子渠首；下游托克逊境内由白杨河干流调节，艾丁湖等生态需水量分别为4256万m3、1.35m3/s、32%和小草湖渠首。白杨河流域年生态需水7880万m3，生态基流2.50m3/s，生态水占年均径流量17%，分析结果为流域生态环境管理保护提供依据。 Abstract:The Baiyang River Basin extends across two administrative districts including Dabancheng in the upper reaches of Urumqi city and Tuokesun County of Turpan City in the lower reaches, Xinjiang. The upper Dabancheng district is located in the dry area of alluvial and proluvial intermontane basin in front of Bogda peak of Tianshan Mountain. Many branches of source streams converge at the mouth of the southern end of the basin, and form the downstream from the gorge. Many tributaries supply the main stream of Baiyang River along the way. Baiyang River passes through Tuokesun County in the extremely arid Gobi desert and ends at Turpan City-Ayding Lake, one of the few typical irrigation areas in China which spans the superposition of drought and extreme drought. The effective utilization of water resources and protection of water ecological environment play an important role. According to the naturally ecological environment attributes formed by the river water system and the river water intake project nodes, Penman-Monteith ecological water demand quota, satellite remote sensing area identification, and hydrological year distribution method were used to analyze and evaluate water demand of the ecological environment vegetation, river ecological base flow and its regulation sections in the upper and lower reaches of the basin. The results show that the annual ecological water demand, ecological base flow, annual runoff proportion, and control section of Heigou River in Dabancheng district are 921 thousand m3, 0.29 m3/s, 18%, and Heigoutou section respectively; those of Aksu River are 1048 ten thousand m3, 0.33 m3/s, 12%, and Aksu canal head; those of Gaoyazi River are 862 ten thousand m3, 0.27 m3/s, 12%, and Gaoyazi channel head; and those of Ayding Lake are 4256 ten thousand m3, 1.35 m3/s, 32%, and the head of Xiaocaohu, where the downstream Tuokesun is regulated by the main stream of Baiyang River. The annual ecological water demand of Baiyang River Basin is 7880 ten thousand m3, the ecological base flow is 2.50 m3/s, and the ecological water accounts for 17% of the annual runoff. The results provide the basis for the management and protection of ecological environment in the basin. 参考文献 相似文献 引证文献

A Probe into Ecological Base Flow of the Intersection of Qianhe-Weihe River in Baoji City, China

The prior remediation of the Baoji section of the Weihe River has significantly improved the river’s flood control and drainage, water and soil pollution control, and wetland environment. However, the uneven distribution of water resources in time has led to the inability to effectively guarantee the ecological base flow of the river during dry season, which has affected the ecological and social functions of the intersection of Qianhe-Weihe River. The maintenance of the ecological base flow of the intersection of Qianhe-Weihe River is to ensure the ecological health of the river, the function of the wetland ecosystem and the basic flow of the social and economic development of Baoji City. It should start from saving water resources, improving water use efficiency, strengthening water distribution and management, and construction of water conservancy control projects. Improve.

Multi-objective ecological operation of cascade reservoirs based on MGCL-PSO algorithm

The reasonable utilization of river water resources requires the joint operation of cascade reservoirs. Aiming at power generation and ecological environment protection, taking the Qingjiang cascade reservoir group as the research object, a multi-objective optimization model for maximum power generation considering ecological base flow and minimum ecological flow changed is established. The results of the multi group cooperation operation particle swarm optimization (MGCL-PSO) model based on population cooperation show that the multi-objective of power generation and ecology can achieve a better balance by slightly reducing the power generation. Several schemes with good convergence are obtained from the calculation results, which provide a reference for the operation of cascade reservoirs.

Optimal reservoir operation based on hydrological and hydraulic methods incorporating the multiple water replenishment process

A reservoir usually functions as multi-objectives. Different objective has various requirement in water volume and temporals process due to the fact that some objectives require different constant base flow in different months and some objectives demand ephemeral flood pulse. How to balance reservoir functioning and water allocation of multiple targets has become increasingly significant at present. In the past, the multi-objectives operation was usually designed based on water quantity balance, neglecting the coupling with the hydrodynamic process. Sometimes the coupling is so important for some ecological factors and the neglecting may result in failure to meet the hydraulic requirements of the downstream ecological environment. By coupling the hydrologic and hydrodynamic methods, an integrated reservoir model for multiple-objectives optimal operation was presented including water balance model, one-dimensional unsteady flow model, two-dimensional depth-averaged model and ecological baseflow model. The different process demands include water allocation at the dam site, unsteady flow process at different sections downstream the dam site. Taking a reservoir in northern China as an example, the minimum change of the hydrological process in the river mouth section was set as the objective function for the optimal operation. Regarding the demand for aquatic organisms, the low and high baseflow schemes were suggested by the comprehensive use of different ecological flow methods (the Tennant method, the flow duration curve method and the wetted perimeter method). According to the ecological flooding during the wetland water supplement, the Wetland Water Replenishment Model was applied to calculate the replenishment process under different flood cases. The Lake Water Replenishment Model was used for flow scheduling of the downstream lake. Regarding the wet years, the objective functions at the river mouth section were 16.0% with the low baseflow scheme and 15.5% with the high baseflow scheme, whereas for the dry years, it is 18.2% with the low baseflow scheme and 15.5% with the high baseflow scheme. Comparison showed that the high baseflow scheme was optimal for the reservoir operation. The result could provide a reference for decision-makers in reservoir scheduling design. It shows that the coupling of hydraulic and hydrological methods could provide a more reliable basis for reservoir optimal operation.

Quantitative Determination of Some Parameters in the Tennant Method and Its Application to Sustainability: A Case Study of the Yarkand River, Xinjiang, China

Analysis of basic eco-environmental water requirements (BEEWRs) along inland rivers characterized by extreme aridity can provide a theoretical basis for sustaining riverine ecosystems stressed by increasingly dry conditions and human activity. In the past, analyzing the ecological base flow as determined by the Tennant method was the predominant method used to calculate the BEEWR of a river. However, some parameter values within this method are determined subjectively, increasing uncertainty in the estimated values. In this paper, quantitative methods for these subjectively determined parameters are proposed and used to analyze the BEEWR of the Yarkand River, Xinjiang, China. The results demonstrate that: (1) the flood and non-flood seasons of a river can be delineated by analyzing the increase rate of monthly runoff as compared to the monthly runoff of the previous month; (2) the ecological base flow standard in the Tennant method can be more quantitatively determined by comparing the BEEWR for each ecological base flow standard to the annual average river loss, where the BEEWR must exceed the annual average river loss; and (3) BEEWRs of other up- and downstream river reaches can be obtained using the formula “BEEWR in the next downstream section equals the BEEWR in the last section minus the river loss between these two sections”.

Quantity of Reasonable Distribution of River Ecological Basic Flow Considering the Economic Value of its Own Ecological Functions: a Case Study in the Baoji Section of the Weihe River, China

Reasonable allocation of ecological water and water economics has become a significant challenge for the water resource decision-makers. In this study we propose an approach to assess the quantity of reasonable distribution of the river ecological basic flow using the economic value of its own ecological function. Firstly, water resource is divided into two parts: (i) water resources used for the river ecological basic flow, its economic value was calculated using the results of a reference method; and (ii) water resources used for economic water use, and we calculated its economic benefit; (iii) By using the principle of benefit maximization, we determine the most reasonable distribution of the river ecological basic flow. The Baoji section of the Weihe River, the largest tributary of the Yellow River, Northeast China, is used as a case-study to calculate the reasonable distribution of the river ecological basic flow. The health status of the river and disadvantages of the calculation model are also analyzed. Results indicate that the reasonable allocation of the river ecological basic flow in the Baoji section of the Weihe River is 33.83% of the amount of water resources in the Linjiacun hydrologic station. Based on the calculation of the different functions of the river ecological basic flow, the reasonable distribution can meet the basic environmental functions of rivers, and can result in healthy development of basin. Results also provide a quantitative basis for water resource management in relation to water distribution in the Weihe River.

A conceptual decision-making for the ecological base flow of rivers considering the economic value of ecosystem services of rivers in water shortage area of Northwest China

Understanding how much water should be left in rivers is a hot topic around the world. Here, we proposed a decision-making framework for ecological base flow of rivers considering the total economic value of economic service functions and ecological service functions of rivers system. This framework mainly includes three key steps. Firstly, we analyzed the ecological services functions of rivers system (i.e., water used for the ecological base flow of rivers) and economic service functions (i.e., water used for economic sectors) and explained their relationship. Secondly, we calculate the economic values of economic service functions and ecological services functions of rivers system, respectively. Finally, we determined the recommended ecological base flow of rivers by reaching the maximum value in the change process of the total economic value of the ecological and economic services functions of rivers system. We applied this framework to determine the river ecological base flow in the Baoji Section of Weihe River, which is the largest tributary of the Yellow River, Northwest China. The calculations results revealed that the recommended ecological base flow of rivers is 35.02% of the natural runoff in Baoji section of Weihe River. This work can provide a valuable reference for decision-making the ecological base flow of river in the water shortage area of Northwest China.

A Multi-Objective and Equilibrium Scheduling Model Based on Water Resources Macro Allocation Scheme

A multi-objective and equilibrium scheduling model is established based on water resources macro allocation (WRMAA) scheme to describe the scheduling process accurately in the specific scheduling period. The proposed coupling method sets the WRMAA schemes as the boundary data of the water resources micro scheduling (WRMIS) model and some indicators are used to couple WRMAA and WRMIS models in terms of objective functions, constraints and time series. The runoff deviation factor of ecological node (RDFEN) is brought into the coupling process in order to reflect the ecological scheduling effects. At last, the proposed model is successfully applied to the regional water resources scheduling in Jinan of Shandong Province, China, on a ten-day basis. The results reveal that the ecological base flow should be taken into account in normal and moderately dry years for the short-term planning period, and it should be recommended for the long-term planning period whatever the water condition is. The water deficit ratio of the long-term planning period is much lower than that of the short-term planning period, which verifies its superiority. Hence, the proposed model provides an effective approach to achieving the coordination of macro planning and micro scheduling management of future water resources, especially for the specific scheduling period.

Compensation for Agricultural Economic Losses Caused by Restoration of Healthy Eco-Hydrological Sequences of Rivers

The rational allocation of ecological and economic water is a topic of high interest for water resource sciences. Taking into consideration the difficulties to maintain the basic ecologic functions of rivers, we propose a calculation model for compensation for agricultural economic losses by restoration of the healthy eco-hydrological sequences of rivers. Firstly, healthy eco-hydrological sequence of rivers was constructed by assessing the response relationship between hydrological processes and ecological functions of ecological base flow of rivers. Following, the ecological water shortage was analyzed qualitatively and quantitatively. Finally, the compensation for agricultural economic losses caused by restoration of healthy eco-hydrological sequence of rivers was calculated. Taking the Baoji section of the Weihe River as a case study, compensation for agricultural economic losses caused by the recovery of the healthy eco-hydrological sequence of rivers were calculated and further analyzed. The results show that the current water diversion in the area of study is excessive and the ecological water shortage is relatively obvious. The compensation for agricultural economic losses caused by the recovery of healthy eco-hydrological sequence of rivers mainly focus on the non-flood season, which is up to 218 million yuan for 2009 year.

Study on Ecological Water Demand Evaluation of Typical Mountainous Rivers in Zhejiang Province—Taking Kaihua River as an Example

In view of the ecological environental problems and protection needs of mountainous rivers in Zhejiang province, a suitable ecological water demand evaluation system was established based on investigation and monitoring. Taking the Kaihua river as an example, the research on ecological water demand and the current situation evaluation were carried out. The main types of ecological water demand in Majin River are ecological basic flow and lake wetland outside the river, and instream flow and water demands for water quality in Zhongcun river. In the wet season each ecological water demand is 18.05m3/s and 2.56m3/s, and in the dry season is 3.00m3/s and 0.61m3/s. Three indexes of flow, duration and occurrence time are used to evaluate the ecological water demand. The degree of ecological water demand in the past three years is low level of satisfaction. Meanwhile the existing problems are analyzed, put forward reasonable measure and suggestions.

Towards sustainable water regulation based on a distributed hydrological model for a heavily polluted urban river, northwest China

Abstract The Qinling Mountains are located in a transition zone between (semi)-arid regions in north China and humid regions in south China. The water resource and water ecology of regional rivers are strongly affected by climate change and human activity. In this paper, the stochastic simulation of river water regulation was performed and an optimal water regulation scheme of rubber dam projects was developed by establishing a multi-objective stochastic constraint water regulation model of rubber dam projects based on the coupling of a distributed hydrological model and a water balance model. Results show that a ∼40% reduction of water occurred in the lower river channel due to the operation of water supply project in the upper reach and impoundment by rubber dam projects in the lower reaches. This water reduction was associated with decreased water environment self-purification capacity and serious deterioration of water quality for smaller ecological basic flow and mean flow velocity. By establishing a multi-objective stochastic constraint programming model, the average velocity and the ecological basic flow at different adjusting heights of rubber dams are determined. The regulation scheme of rubber dam projects we propose in this paper may optimize the current river water management strategies and help to improve the river water quality environment in urban rivers.

THOUGHTS ON ECOLOGICAL WATERSHED PLANNING UNDER THE TERRITORIAL SPATIAL PLANNING

The author firstly points out several problems that commonly exist in China’s watersheds and the urgent need for multidisciplinary collaboration in ecological planning. The theories and practices on watershed ecological planning are reviewed respectively from the aspects of waterway planning, natural river and wetland protection, ecological baseflow recovery, nonpoint source pollution reduction, and biodiversity protection. The author suggests that if we could reserve multi-functional ecological zone in the new territorial spatial planning by multidisciplinary collaboration, ecological goals including flood control, water quality improvement, ecological base flow provision, and biodiversity protection could be achieved. In this comprehensive solution, only when water bodies and associated habitats such as the ground and underground, upstream and downstream, and rivers and banks are coordinated as a whole, it will generate multiple ecological benefits. Finally, the author believes that planners and designers have the ability to solve ecological problems. To fulfill this vision, we must call for collaboration between land planning and ecological watershed planning in the process of territorial spatial planning.