Calculation method of multi-objective ecological water delivery in the lower reaches of a river basin

Abstract

The invention discloses a method for calculating the multi-objective ecological water delivery in the downstream of a river basin, which comprises the following steps: S1: acquiring basic information of a water resource system in the downstream of the river basin; and determining the lake area of ​​the target study area this year according to the ecological demand of the target study area; S2: constructing a MIKE 11 hydrodynamic model and a MIKE SHE hydrological system model of the downstream of the river basin according to the basic information of the water resource system in the downstream of the river basin; S3: calculating the total loss of ecological water transported from the upstream to the target study area according to the MIKE 11 hydrodynamic model and the MIKE SHE hydrological system model of the downstream of the river basin; S4: acquiring the lake area of ​​the target study area in the previous year according to data of different hydrological years of the target study area; S5: calculating the amount of water entering the lake required to maintain the lake area of ​​the target study area this year according to the lake area of ​​the target study area in the previous year; and S6: calculating the amount of water discharged from the upstream of the river basin according to the total loss and the amount of water entering the lake required to maintain the lake area this year.

Description

Technical Field

[0001] The present invention relates to the technical field of water resource dispatching, and in particular to a method for calculating multi-objective ecological water delivery in a downstream of a river basin. Background Art

[0002] The Tarim River is the longest inland river in China. Its lower reaches are located in the fortress of the southern route of the "Silk Road". It is the only way for Xinjiang to connect with the second strategic channel inland (including: Ruoqiang-Yining National Highway 218, Korla-Golmud Railway, Korla-Ruoqiang Expressway). It has a unique geographical location and an important strategic position. The green corridor formed by the desert riverbank poplar forest in the lower reaches is a natural ecological barrier that blocks the merging of the two deserts of Taklimakan and Kumtag, and its ecological status is irreplaceable. However, since the 1950s, due to climate change and intensified interference from human activities, especially after the construction of the Daxihaizi Reservoir in 1972, the 350km river channel in the lower reaches has been cut off, the tail Lop Nur and Taitema Lake have dried up one after another, the land desertification has intensified, and the area of ​​desert riverbank poplar forest has been shrinking. Therefore, the lower reaches of the Tarim River are famous for their distinct regional characteristics, extremely fragile ecosystems and prominent ecological problems.

[0003] In order to save the downstream ecosystem that was on the verge of collapse, the basin implemented a recent comprehensive management in 2001. With the combined effect of human efforts and abundant natural water, the ecological environment of the lower reaches of the Tarim River has been initially improved. However, there is still a long way to go to protect and restore the ecology of the lower reaches of the Tarim River. The vegetation coverage of the green corridor is very low, the ecological stability is poor, and the ecological function is weak. The roads and railways along the route are still facing a major crisis of frequent sand burial.

[0004] In the process of ecological environment governance in the lower reaches of the Tarim River, the scheduling of ecological water transfer is the most critical. The traditional water transfer method only regulates the ecological water transfer through macro means, which cannot achieve precise control, resulting in ineffective evaporation of precious water resources in arid areas and inability to maximize the use of ecological water for vegetation restoration. Summary of the invention

[0005] In response to the above-mentioned problems in the prior art, the present invention aims to provide a method for calculating the multi-objective ecological water transfer volume in the downstream of the basin, which solves the problem that the traditional water transfer method only regulates the ecological water transfer volume through macroscopic means and cannot maximize the use of ecological water for vegetation restoration.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows: a method for calculating the multi-objective ecological water delivery in the downstream of a river basin is provided, which comprises the steps of:

[0007] S1: Obtain basic information on the water resources system in the lower reaches of the basin; and determine the lake area of ​​the target study area this year based on the ecological needs of the target study area;

[0008] S2: Based on the basic information of the water resources system in the downstream of the basin, the MIKE 11 hydrodynamic model and the MIKE SHE hydrological system model in the downstream of the basin are constructed;

[0009] S3: Based on the MIKE 11 hydrodynamic model and the MIKE SHE hydrological system model in the downstream of the basin, the total loss of ecological water transported from the upstream to the target study area was calculated;

[0010] S4: Based on the data of different hydrological years in the target study area, obtain the lake area of ​​the target study area in the previous year;

[0011] S5: Based on the lake surface area of ​​the target study area in the previous year, calculate the amount of water entering the lake required to maintain the lake surface area of ​​the target study area this year;

[0012] S6: Calculate the amount of water discharged from the upstream of the basin based on the total loss and the amount of water entering the lake required to maintain the lake surface area this year.

[0013] Furthermore, the basic information of the water resources system in the downstream of the basin includes hydrological data, engineering geological and topographic data.

[0014] Further, in step S3, the input data of the MIKE 11 hydrodynamic model include river network files, cross-section files and boundary conditions, and the output data are the water volume and water level in the downstream of the basin in different hydrological years;

[0015] The input data of the MIKE SHE hydrological system model include DEM, land use data, soil and hydrogeological data, rainfall and temperature data, meteorological data, potential evapotranspiration data and soil, vegetation attribute data and groundwater data. The coupled simulation of MIKE 11 and MIKE SHE has output data including soil water consumption, groundwater uplift, vegetation transpiration and river surface evaporation. The total loss of ecological water from the upstream to the target study area is calculated based on the output data.

[0016] Furthermore, the soil water consumption in the target study area this year is W 土壤 The calculation formula is:

[0017] W 土壤 =M×S1×D×L

[0018] Among them, M is the unit soil moisture content in the downstream of the basin; S1 is the water absorption area of ​​the soil in the downstream of the basin; D is the thickness of the water-absorbing soil in the downstream of the basin; L is the length from the upstream of the basin to the target study area;

[0019] The groundwater uplift in the target study area this year is W 地下水 The calculation formula is:

[0020] W 地下水=N×Q;

[0021] N = W1 / Q1;

[0022] Among them, Q is the amount of water discharged from the upstream of the basin this year; N is the ratio of groundwater uplift; W1 is the average value of groundwater uplift in the target study area in the previous year, and Q1 is the average value of water discharged from the upstream of the basin in the target study area in the previous year;

[0023] The target study area this year is the transpiration water consumption of vegetation W 植被 The calculation formula is:

[0024] NI=6.1376+2.2069W1+0.2715Q1+0.2813W1 2 -0230 Q1 2 , R 2 =0.96

[0025] VC=(NI-NDVIsail) / (NDVIveg-NDVIsail)

[0026]

[0027] VPD=Ee

[0028] W 植被 =VC·WUE

[0029] Among them, NI is the normalized vegetation index, VC is the vegetation coverage of the target study area; NDVIsail is the NDVI value of the bare land pixel without vegetation coverage in the target study area; NDVIveg is the NDVI value of the pixel with full vegetation coverage in the target study area; the δ 13 C ratio; δ 13 C a The δ 13 C ratio; h is the fractionation of CO2 during the diffusion process of vegetation leaves; b is the carbon isotope fractionation during the carboxylation process of plants; δ 13 C p δ 13 C ratio; VPD is the vapor pressure difference between the inside and outside of the blade; E is the saturated vapor pressure at the same temperature; e is the actual vapor pressure;

[0030] The target evaporation of the river water surface in the study area this year is W 河道 The calculation formula is:

[0031] W 河道 = k·L

[0032] k=(W1-W2) / l

[0033] Among them, k is the water consumption rate per unit river length, W1 is the inflow of the upper section of the river, and W2 is the outflow of the lower section of the river;

[0034] W 总损失量 =W 土壤 +W 地下水 +W 植被 +W 河道

[0035] Among them, W 总损失量 It is the total loss of ecological water transported from the upstream to the target study area.

[0036] Furthermore, the calculation formula for the amount of water V required to maintain the lake surface area in the target study area this year is:

[0037]

[0038] Among them, S1 is the area corresponding to the lake surface contour line of the target study area in the previous year; S2 is the area corresponding to the lake surface contour line of the target study area this year; d is the height difference between the two contour lines.

[0039] Furthermore, the calculation formula for the discharge volume Q in the upstream of the basin is:

[0040] Q=(W 土壤 +W 植被 +W 河道 +V) / (1-N).

[0041] Furthermore, the calculation formula for the saturated water vapor pressure E at the same temperature is:

[0042] E=0.611×10 17.502T / (240.97+T)

[0043] Where T is the air temperature.

[0044] Furthermore, the calculation formula for the saturated water vapor pressure E at the same temperature is:

[0045] E=e / RH

[0046] Among them, e is the actual water vapor pressure; RH is the relative humidity of the air.

[0047] The beneficial effects of the present invention are as follows: the method for calculating the multi-objective ecological water transfer in the downstream of the basin in the present invention obtains the upstream water discharge in the basin by respectively calculating the total loss of ecological water transported from the upstream to the target study area and the amount of water entering the lake required for the target study area to maintain the lake area this year. This is conducive to the coordinated realization of comprehensive goals such as water security, water resources, and water environment, ensuring the ecological water demand of the target study area, building a water resources scheduling system, and accurately controlling the ecological water transfer in the target study area. While saving water resources, it can effectively support the ecological construction of the target study area, reduce or eliminate the impact of the increasingly severe water resources contradictions on ecological restoration, and achieve ecological protection of the target study area. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a flow chart of the method for calculating the multi-objective ecological water delivery in the downstream of the basin in the present invention. DETAILED DESCRIPTION

[0049] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0050] like Figure 1 As shown, the present invention provides a method for calculating the multi-objective ecological water delivery in the downstream of a river basin, which comprises the following steps:

[0051] S1: Obtain basic information on the water resources system in the downstream of the basin; and determine the lake area of ​​the target study area this year based on the ecological needs of the target study area; specifically, the basic information on the water resources system in the downstream of the basin includes hydrological data, engineering geological and topographic data.

[0052] S2: Based on the basic information of the water resources system in the downstream of the basin, the MIKE 11 hydrodynamic model and the MIKE SHE hydrological system model of the downstream of the basin are constructed; MIKE 11 is a top-level river simulation software, covering a wider range of applications than any other river simulation software. MIKE SHE is a model system further developed by the Danish Hydraulics Institute in the early 1990s based on the SHE model. It is a comprehensive, deterministic and physically meaningful distributed hydrological system model.

[0053] S3: Based on the MIKE 11 hydrodynamic model and the MIKE SHE hydrological system model of the downstream basin, the total loss of ecological water transported from the upstream to the target study area is calculated; specifically, the input data of the MIKE 11 hydrodynamic model include river network files, cross-section files and boundary conditions, and the output data are the water volume and water level of the downstream basin in different hydrological years;

[0054] The input data of the MIKE SHE hydrological system model include DEM, land use data, soil and hydrogeological data, rainfall and temperature data, meteorological data, potential evapotranspiration data, soil, vegetation attribute data and groundwater data. The coupled simulation of MIKE 11 and MIKE SHE can realize the calculation of the water balance process in the downstream of the basin in different water inflow years and obtain output data. The output data include soil water consumption, groundwater uplift, vegetation transpiration water consumption, and river surface evaporation. The total loss of ecological water from the upstream to the target study area is calculated based on the output data.

[0055] Specific sources of input data: DEM is the digital elevation model of the downstream of the basin, which can be obtained through the National DEM Data Resource Center; land use data is extracted through the interpretation of Landsat TM; soil data is extracted through the interpretation of the World Soil Database (HWSD); hydrogeological data includes geological survey data and hydraulic conductivity; rainfall and temperature data meteorological data come from the meteorological station data of the China Meteorological Network; potential evapotranspiration data is calculated using the Penman formula; vegetation attribute file. The parameters required for ETV mainly include leaf area index (LAI) and root zone depth (RD), and the leaf area index is obtained using GLASS remote sensing data.

[0056] The specific contents of calculating the total loss of ecological water transported from upstream to the target study area are as follows:

[0057] The soil water consumption in the target study area this year is W 土壤 The calculation formula is:

[0058] W 土壤 =M×S1×D×L

[0059] Among them, M is the unit soil moisture content in the downstream of the basin; S1 is the water absorption area of ​​the soil in the downstream of the basin; D is the thickness of the water-absorbing soil in the downstream of the basin; L is the length from the upstream of the basin to the target study area;

[0060] The groundwater uplift in the target study area this year is W 地下水 The calculation formula is:

[0061] W 地下水 =N×Q;

[0062] N = W1 / Q1;

[0063] Among them, Q is the amount of water discharged from the upstream of the basin this year; N is the ratio of groundwater uplift; W1 is the average value of groundwater uplift in the target study area in the previous year, and Q1 is the average value of water discharged from the upstream of the basin in the target study area in the previous year;

[0064] The target study area this year is the transpiration water consumption of vegetation W 植被 The calculation formula is:

[0065] NI=6.1376+2.2069W1+0.2715Q1+0.2813W1 2 -0230 Q1 2 , R 2 =0.96

[0066] VC=(NI-NDVIsail) / (NDVIveg-NDVIsail)

[0067]

[0068] VPD=Ee

[0069] W 植被 =VC·WUE

[0070] Among them, NI is the normalized vegetation index, VC is the vegetation coverage of the target study area; NDVIsail is the NDVI value of the bare land pixel without vegetation coverage in the target study area; NDVIveg is the NDVI value of the pixel with full vegetation coverage in the target study area; the δ 13 C ratio; δ 13 C a The δ 12 C ratio; h is the fractionation of CO2 during the diffusion process of vegetation leaves; b is the carbon isotope fractionation during the carboxylation process of plants; δ 13 C p δ 13 C ratio; VPD is the water vapor pressure difference inside and outside the blade; E is the saturated water vapor pressure at the same temperature; e is the actual water vapor pressure.

[0071] In this scheme, two methods for calculating the saturated water vapor pressure E at the same temperature are provided. The first calculation formula for the saturated water vapor pressure E at the same temperature is:

[0072] E=0.611×10 17.502T / (240.97+T)

[0073] Where T is the air temperature.

[0074] The second calculation formula for the saturated water vapor pressure E at the same temperature is:

[0075] E=0.611×10 17.5027 / (2+0.9 / +T)

[0076] Where T is the air temperature.

[0077] The first implementation method of saturated water vapor pressure E is calculated only based on the real-time air temperature. It does not need to collect more data and has a lower workload. The data collected by the second implementation method is mainly real-time. Although it requires slightly more data, the calculation is more accurate.

[0078] The target evaporation of the river water surface in the study area this year is W 河道 The calculation formula is:

[0079] W 河道 = k·L

[0080] k=(W1-W2) / l

[0081] Among them, k is the water consumption rate per unit river length, W1 is the inflow of the upper section of the river, and W2 is the outflow of the lower section of the river;

[0082] W 总损失量 =W 土壤 +W 地下水 +W 植被 +W 河道

[0083] Among them, W 总损失量 It is the total loss of ecological water transported from the upstream to the target study area. By calculating the total loss of ecological water transported from the upstream to the target study area and the amount of water entering the lake required to maintain the lake surface area of ​​the target study area this year, the amount of water discharged from the upstream of the basin can be obtained, which is conducive to the overall realization of comprehensive goals such as water security, water resources, and water environment, ensuring the ecological water demand of the target study area, accurately controlling the ecological water delivery of the target study area, saving water resources, and effectively supporting the ecological construction of the target study area.

[0084] S4: Based on the data of different hydrological years in the target study area, the lake area of ​​the target study area in the previous year was obtained; the lake area of ​​the target study area in the previous year was extracted using the remote sensing image data of different hydrological years in the target study area. Here, in order to facilitate subsequent calculations, the average value of the lake area of ​​the target study area in the previous year can be taken to make the calculation more accurate.

[0085] S5: Based on the lake surface area of ​​the target study area in the previous year, calculate the amount of water entering the lake required to maintain the lake surface area of ​​the target study area this year; specifically, the calculation formula for the amount of water entering the lake V required to maintain the lake surface area of ​​the target study area this year is:

[0086]

[0087] Among them, S1 is the area corresponding to the lake surface contour line of the target study area in the previous year, that is, the average value of the lake surface area of ​​the target study area in the previous year; S2 is the area corresponding to the lake surface contour line of the target study area this year, that is, the average value of the lake surface area of ​​the target study area this year; d is the height difference between the two contour lines.

[0088] S6: Calculate the amount of water discharged from the upper reaches of the basin based on the total loss and the amount of water entering the lake required to maintain the lake surface area this year. Specifically, the calculation formula for the amount of water discharged from the upper reaches of the basin, Q, is:

[0089] Q=(W 土壤 +W 植被 +W 河道 +V) / (1-N).

[0090] In order to maintain the lake area of ​​the target study area at a preset value, the amount of water Q that needs to be discharged from the upstream of the basin to the downstream of the basin can meet the inflow of water into the lake in the target study area. The calculation method of the multi-objective ecological water transfer volume in the downstream of the basin in the present invention calculates the total loss of ecological water transported from the upstream to the target study area and the inflow of water required to maintain the lake area of ​​the target study area this year, so as to obtain the upstream water transfer volume of the basin. This is conducive to the coordinated realization of comprehensive goals such as water security, water resources, and water environment, ensuring the ecological water demand of the target study area, building a water resources scheduling system, accurately controlling the ecological water transfer volume of the target study area, saving water resources, and effectively supporting the ecological construction of the target study area, reducing or eliminating the impact of the increasingly severe water resources contradictions on ecological restoration, and realizing the ecological protection of the target study area.

Claims

1. The calculation method of multi-objective ecological water delivery in the downstream of the basin is characterized by: Includes steps: S1: Obtain basic information on the water resources system in the lower reaches of the basin; and determine the lake area of ​​the target study area this year based on the ecological needs of the target study area; S2: Based on the basic information of the water resources system in the downstream of the basin, the MIKE 11 hydrodynamic model and the MIKE SHE hydrological system model in the downstream of the basin are constructed; S3: According to the MIKE 11 hydrodynamic model and the MIKE SHE hydrological system model of the downstream of the basin, the total loss of ecological water from the upstream to the target study area is calculated; in step S3, the input data of the MIKE 11 hydrodynamic model include river network files, section files and boundary conditions, and the output data are the water volume and water level of the downstream of the basin in different hydrological years; the input data of the MIKE SHE hydrological system model include DEM, land use data, soil and hydrogeological data, rainfall and temperature data meteorological data, potential evapotranspiration data and soil, vegetation attribute data and groundwater data, coupled simulation of MIKE 11 and MIKE SHE, and the output data include soil water consumption, groundwater uplift, vegetation transpiration water consumption, and river surface evaporation; the total loss of ecological water from the upstream to the target study area is calculated based on the output data; S4: Based on the data of different hydrological years in the target study area, obtain the lake area of ​​the target study area in the previous year; S5: Based on the lake surface area of ​​the target study area in the previous year, calculate the amount of water entering the lake required to maintain the lake surface area of ​​the target study area this year; S6: Calculate the amount of water discharged from the upstream of the basin based on the total loss and the amount of water entering the lake required to maintain the lake surface area this year.

2. The method for calculating the multi-objective ecological water delivery in the downstream of a river basin according to claim 1 is characterized in that: In step S1, the basic information of the downstream water resources system of the basin includes hydrological data, engineering geological and topographic data.

3. The method for calculating the multi-objective ecological water delivery in the downstream of a river basin according to claim 2 is characterized in that: The soil water consumption in the target study area this year is W 土壤 The calculation formula is: IN 土壤 =M×S1×D×L Among them, M is the unit soil moisture content in the downstream of the basin; S1 is the water absorption area of ​​the soil in the downstream of the basin; D is the thickness of the water-absorbing soil in the downstream of the basin; L is the length from the upstream of the basin to the target study area; The groundwater uplift in the target study area this year is W 地下水 The calculation formula is: IN 地下水 = N×Q ; N=W1 / Q1; Among them, Q is the amount of water discharged from the upstream of the basin this year; N is the ratio of groundwater uplift; W1 is the average value of groundwater uplift in the target study area in the previous year, and Q1 is the average value of water discharged from the upstream of the basin in the target study area in the previous year; The target study area this year is the transpiration water consumption of vegetation W 植被 The calculation formula is: NI =6.1376+2.2069 W1+0.2715 Q1+0.2813 W1 2 -0230 Q1 2 , R 2 =0.96 VC=( NI -NDVIsail) / (NDVIveg-NDVIsail) W 植被 = VC▪ in, NI is the vegetation normalized index, VC is the vegetation coverage of the target study area; NDVIsail is the NDVI value of the bare land pixel without vegetation coverage in the target study area; NDVIveg is the NDVI value of the pixel with full vegetation coverage in the target study area; the stable isotope mass spectrometer is used to measure the NDVI of the plant with the largest planting area in the study area. ratio; Air in the target study area ratio; h It is the fractionation of CO2 during the diffusion process in vegetation leaves; b For carbon isotope fractionation during plant carboxylation; In plant tissue ratio; VPD is the vapor pressure difference between the inside and outside of the blade; E is the saturated water vapor pressure at the same temperature; e is the actual water vapor pressure; The target evaporation of the river water surface in the study area this year is W 河道 The calculation formula is: W 河道 =k▪ L k=(W1-W2) / l Among them, k is the water consumption rate per unit river length, W1 is the water inflow of the upper section of the river, and W2 is the outflow of the lower section of the river; IN 总损失量 = In 土壤 + In 地下水 + In 植被 + In 河道 Among them, W 总损失量 It is the total loss of ecological water transported from the upstream to the target study area.

4. The method for calculating the multi-objective ecological water delivery in the downstream of a river basin according to claim 3 is characterized in that: The calculation formula for the amount of water V required to maintain the lake surface area in the target study area this year is: Among them, S1 is the area corresponding to the lake surface contour line of the target study area in the previous year; S2 is the area corresponding to the lake surface contour line of the target study area in this year; d is the height difference between two contour lines.

5. The method for calculating the multi-objective ecological water delivery in the downstream of a river basin according to claim 4 is characterized in that: The calculation formula for the water discharge Q in the upstream of the basin is: Q=(W 土壤 + W 植被 + W 河道 +V) / (1-N)。 6. The method for calculating the multi-objective ecological water delivery in the downstream of a river basin according to claim 5 is characterized in that: The saturated water vapor pressure at the same temperature E The calculation formula is: in, T is the air temperature.

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