Ecological water demand calculation method considering habitat of dominant species and groundwater supply

Abstract

The invention discloses an ecological water demand calculation method considering habitats of dominant species and groundwater supply. The method comprises the following steps: screening dominant species of a river channel; determining the ecological flow velocity and the ecological water depth of the dominant species; calculating the groundwater supply water demand of the river profile; and calculating the ecological water demand based on the ecological flow velocity and the ecological water depth of the dominant species and the groundwater supply water demand of the river profile. According to the method, the requirements of aquatic organisms on suitable habitat conditions are considered, the groundwater supply water demand is supplemented, the method is reasonable and accurate, a basis can be provided for scientific management and control of river ecological flow, and the protection work of river ecological system health is supported.

Description

Technical Field

[0001] The invention belongs to the field of ecological environment protection, and specifically relates to an ecological water demand calculation method taking into account the habitat of dominant species and groundwater recharge. Background Art

[0002] With the rapid development of economy and the improvement of people's living standards, the social water demand is growing. The series of cross-regional and cross-basin water diversion projects and cascade development projects implemented to meet the water demand will inevitably bring pressure to the guarantee of ecological water demand. Therefore, it is urgent to deepen the understanding of river ecological water demand and reasonably calculate it, strictly control the ecological flow and maintain the normal operation of river ecosystem functions.

[0003] At present, researchers have conducted a large number of studies related to ecological water demand, and the calculation methods used for river ecological water demand include hydrological method, hydraulic method and habitat method. However, many methods still have certain defects and shortcomings, such as lack of consideration of suitable habitats for aquatic organisms, calculation of ecological water demand based on only one factor, and neglect of groundwater recharge demand, which leads to poor rationality and accuracy of calculation, making these methods face great obstacles in practical application. Summary of the invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the background technology, the present invention discloses a method for calculating ecological water demand taking into account the habitat of dominant species and groundwater recharge. This method takes into account the needs of aquatic organisms for suitable habitat conditions, while supplementing the groundwater recharge demand. It is reasonable and accurate, and can provide a basis for the scientific management and control of river ecological flow, and support the protection of the health of river ecosystems.

[0005] Technical solution: The present invention discloses a method for calculating ecological water demand taking into account the habitat of dominant species and groundwater recharge, comprising the following steps:

[0006] (1) Screening of dominant species in rivers;

[0007] (2) Determine the ecological flow rate and ecological water depth of dominant species;

[0008] (3) Calculate the groundwater recharge requirement of the river profile;

[0009] (4) Calculate the ecological water demand based on the ecological flow velocity, ecological water depth and groundwater recharge demand of the river profile of the dominant species.

[0010] Furthermore, step (1) screens out dominant species in the river through the following model:

[0011] D=ω1×PCT a +ω2×PCT b

[0012] Where D is the dominance of a species; PCT a is the biomass of the species, PCT b is the ratio of the species density in the entire community; ω1 is PCT a The weight of ω2 is PCT b The entropy weight method is used to determine the value of the weight.

[0013] Furthermore, step (2) uses a habitat suitability index based on multiple species to determine the ecological flow rate and ecological water depth of the dominant species obtained in step (1);

[0014]

[0015] Where k is the kth gradient of a habitat environmental factor, k = 1, ..., K, K is the total number of gradients of the habitat environmental factor; i represents the i-th dominant species, i = 1, ..., I, I is the total number of dominant species; n ki is the abundance of the i-th species in the k-th gradient of habitat environmental factors; N i is the abundance of the i-th species in each gradient of habitat environmental factors; P ki is the suitable probability of the i-th species in the k-th gradient; MHSI k It is a habitat suitability index based on multiple species.

[0016] Furthermore, step (3) uses the following formula to calculate the groundwater recharge requirement:

[0017] Q u =Q a -Q b -Q c

[0018] Among them, Q u is the groundwater recharge demand at a certain calculated section of the river, m 3 / s;Q a To calculate the groundwater runoff in the riverbed cover below the aquatic ecological base flow water level at the section, m 3 / s;Q b It is the recharge of groundwater from the mountains on both sides of the river from the dam site to the calculated section to the riverbed during the dry season, or the reverse recharge from the riverbed to the low trough of groundwater from the mountains on both sides of the river, m 3 / s, when groundwater replenishes the riverbed Q b is positive, when the riverbed reverses to the groundwater low trough Q b is a negative value; Q c is the leakage of dam foundation and around dam, m 3 / s.

[0019] Furthermore, Q is calculated using the following formula: a :

[0020] Q a =K1×A d ×i

[0021] Where K1 is the permeability coefficient of the riverbed cover at the calculation section, m / s; A d To calculate the cross-sectional area of ​​groundwater flowing through the riverbed cover below the aquatic ecological base flow water level at the section, m 2 ; i is the hydraulic gradient of the river within a certain range upstream and downstream of the calculation section.

[0022] Furthermore, Q is calculated using the following formula: b :

[0023] Q b =(q1+q2)L

[0024]

[0025] Where q1 is the recharge per unit length of groundwater from the left bank of the river to the riverbed during the dry season, or the reverse recharge per unit length of the riverbed to the groundwater low trough on the left bank of the river, m 2 / s; q2 is the recharge per unit length of the groundwater on the right bank of the river during the dry season from the riverbed to the riverbed per unit length, or the reverse recharge per unit length from the riverbed to the groundwater low trough on the right bank of the river. The calculation process is the same as q1, m 2 / s; L is the length from the dam site to the calculated section, m; K2 is the permeability coefficient of the slope rock and soil, m / s; h1 is the height difference between the relative impermeable layer and the stable water level of the riverside slope in the dry season or the stable water level of the groundwater low trough, m; h2 is the height difference between the relative impermeable layer and the water level of the riverbed in the dry season, m; H1 is the stable water level of the riverside slope in the dry season or the stable water level of the groundwater low trough, m; H2 is the water level of the riverbed in the dry season, m; l is the distance from the riverbed water edge to the stable water level line of the riverside slope in the dry season or the stable water level line of the groundwater low trough, m.

[0026] Furthermore, in step (4), the ecological flow velocity and ecological water depth of the dominant species obtained in steps (1) and (2) are input into the ecological hydraulic radius method, and the groundwater recharge demand of the river profile obtained in step (3) is added to obtain the ecological water demand, and the formula is as follows:

[0027]

[0028] R e =n 3 / 2 ×V e 3 / 2 ×J 3 / 4

[0029] Among them, Q e is the ecological water demand, m3 / s; n is the roughness of the river channel; R e is the hydraulic radius of the river, m; A e is the cross-sectional area of ​​water flow, m 2 ; J is hydraulic slope; V e is the ecological flow velocity, m / s.

[0030] Beneficial effects: Compared with the prior art, the advantages of the present invention are: using the dominance model and the habitat suitability index based on multiple species to determine the ecological flow velocity and ecological water depth, and calculating the groundwater recharge demand through groundwater runoff, the recharge of groundwater from the mountains on both sides of the river to the riverbed or the reverse recharge from the riverbed to the groundwater low troughs on both sides of the river, and the dam foundation and bypass leakage. A new ecological water demand calculation method is proposed, which makes up for the shortcomings of many traditional methods, such as the lack of consideration for suitable habitats for aquatic organisms and the neglect of groundwater recharge demand, and can more reasonably and accurately calculate the ecological water demand of the river. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0032] A method for calculating ecological water demand considering dominant species habitats and groundwater recharge, comprising the following steps:

[0033] Step 1: Screen the dominant species in the river.

[0034] The dominant species in the river are screened out through the following model:

[0035] D=ω1×PCT a +ω2×PCT b

[0036] Where D is the dominance of a species; PCT a is the biomass of the species, PCT b is the ratio of the species density in the entire community; ω1 is PCT a The weight of ω2 is PCT b The entropy weight method is used to determine the value of the weight.

[0037] Step 2: Determine the ecological flow rate and ecological water depth of the dominant species.

[0038] Use the multi-species habitat suitability index to determine the ecological flow rate and ecological water depth of the dominant species obtained in step 1;

[0039]

[0040] Where k is the kth gradient of a habitat environmental factor, k = 1, ..., K, K is the total number of gradients of the habitat environmental factor; i represents the i-th dominant species, i = 1, ..., I, I is the total number of dominant species; n ki is the abundance of the i-th species in the k-th gradient of habitat environmental factors; N i is the abundance of the i-th species in each gradient of habitat environmental factors; P ki is the suitable probability of the i-th species in the k-th gradient; MHSI k It is a habitat suitability index based on multiple species.

[0041] Step 3: Calculate the groundwater recharge demand of the river profile.

[0042] The groundwater recharge requirement is calculated using the following formula:

[0043] Q u =Q a -Q b -Q c

[0044] Among them, Q u is the groundwater recharge demand at a certain calculated section of the river, m 3 / s;Q a To calculate the groundwater runoff in the riverbed cover below the aquatic ecological base flow water level at the section, m 3 / s;Q b It is the recharge of groundwater from the mountains on both sides of the river from the dam site to the calculated section to the riverbed during the dry season, or the reverse recharge from the riverbed to the low trough of groundwater from the mountains on both sides of the river, m 3 / s, when groundwater replenishes the riverbed Q b is positive, when the riverbed reverses to the groundwater low trough Q b is a negative value; Q c is the leakage of dam foundation and around dam, m 3 / s.

[0045] Q is calculated using the following formula a :

[0046] Q a =K1×A d ×i

[0047] Where K1 is the permeability coefficient of the riverbed cover at the calculation section, m / s; A d To calculate the cross-sectional area of ​​groundwater flowing through the riverbed cover below the aquatic ecological base flow water level at the section, m 2 ; i is the hydraulic gradient of the river within a certain range upstream and downstream of the calculation section.

[0048] Q is calculated using the following formula b :

[0049] Q b =(q1+q2)L

[0050]

[0051] Where q1 is the recharge per unit length of groundwater from the left bank of the river to the riverbed during the dry season, or the reverse recharge per unit length of the riverbed to the groundwater low trough on the left bank of the river, m 2 / s; q2 is the recharge per unit length of the groundwater on the right bank of the river during the dry season from the riverbed to the riverbed per unit length, or the reverse recharge per unit length from the riverbed to the groundwater low trough on the right bank of the river. The calculation process is the same as q1, m 2 / s; L is the length from the dam site to the calculated section, m; K2 is the permeability coefficient of the slope rock and soil, m / s; h1 is the height difference between the relative impermeable layer and the stable water level of the riverside slope in the dry season or the stable water level of the groundwater low trough, m; h2 is the height difference between the relative impermeable layer and the water level of the riverbed in the dry season, m; H1 is the stable water level of the riverside slope in the dry season or the stable water level of the groundwater low trough, m; H2 is the water level of the riverbed in the dry season, m; l is the distance from the riverbed water edge to the stable water level line of the riverside slope in the dry season or the stable water level line of the groundwater low trough, m.

[0052] Step 4: Calculate the ecological water demand based on the ecological flow velocity, ecological water depth and groundwater recharge demand of the river profile of the dominant species.

[0053] The ecological flow velocity and ecological water depth of the dominant species obtained in steps 1 and 2 are input into the ecological hydraulic radius method, and the groundwater recharge demand of the river profile obtained in step 3 is added to obtain the ecological water demand. The formula is as follows:

[0054]

[0055] R e =n 3 / 2 ×V e 3 / 2 ×J 3 / 4

[0056] Among them, Q e is the ecological water demand, m 3 / s; n is the roughness of the river channel; R e is the hydraulic radius of the river, m; A e is the cross-sectional area of ​​water flow, m 2 ; J is hydraulic slope; V e is the ecological flow velocity, m / s.

Claims

1. A method for calculating ecological water demand taking into account the habitat of dominant species and groundwater recharge, characterized in that: The following steps are involved: (1) Screening of dominant species in rivers; (2) Determine the ecological flow rate and ecological water depth of dominant species; (3) Calculate the groundwater recharge requirement of the river profile; (4) Calculate the ecological water demand based on the ecological flow velocity, ecological water depth and groundwater recharge demand of the river profile of the dominant species.

2. The method for calculating ecological water demand considering dominant species habitat and groundwater recharge according to claim 1, characterized in that: Step (1) Screen out dominant species in the river using the following model: D=ω1×PCT a +ω2×PCT b Where D is the dominance of a species; PCT a is the biomass of the species, PCT b is the ratio of the species density in the entire community; ω1 is PCT a The weight of ω2 is PCT b The entropy weight method is used to determine the value of the weight.

3. The method for calculating ecological water demand considering habitats of dominant species and groundwater recharge according to claim 1, characterized in that: Step (2) uses a habitat suitability index based on multiple species to determine the ecological flow rate and ecological water depth of the dominant species obtained in step (1); Where k is the kth gradient of a habitat environmental factor, k = 1, ..., K, K is the total number of gradients of the habitat environmental factor; i represents the i-th dominant species, i = 1, ..., I, I is the total number of dominant species; n ki is the abundance of the i-th species in the k-th gradient of habitat environmental factors; N i is the abundance of the i-th species in each gradient of habitat environmental factors; P ki is the suitable probability of the i-th species in the k-th gradient; MHSI k It is a habitat suitability index based on multiple species.

4. The method for calculating ecological water demand considering dominant species habitat and groundwater recharge according to claim 1, characterized in that: Step (3) uses the following formula to calculate the groundwater recharge requirement: Q u =Q a -Q b -Q c Among them, Q u is the groundwater recharge demand at a certain calculated section of the river, m 3 / s;Q a To calculate the groundwater runoff in the riverbed cover below the aquatic ecological base flow water level at the section, m 3 / s;Q b It is the recharge of groundwater from the mountains on both sides of the river from the dam site to the calculated section to the riverbed during the dry season, or the reverse recharge from the riverbed to the low trough of groundwater from the mountains on both sides of the river, m 3 / s, when groundwater replenishes the riverbed Q b is positive, when the riverbed reverses to the groundwater low tank, Q b is a negative value; Q c is the leakage of dam foundation and around dam, m 3 / s.

5. The method for calculating ecological water demand considering habitats of dominant species and groundwater recharge according to claim 4, characterized in that: Q is calculated using the following formula a : Q a =K1×A d ×i Where K1 is the permeability coefficient of the riverbed cover at the calculation section, m / s; A d To calculate the cross-sectional area of ​​groundwater flowing through the riverbed cover below the aquatic ecological base flow water level at the section, m 2 ; i is the hydraulic gradient of the river within a certain range upstream and downstream of the calculation section.

6. The method for calculating ecological water demand considering habitats of dominant species and groundwater recharge according to claim 4, characterized in that: Q is calculated using the following formula b : Q b =(q1+q2)L Where q1 is the recharge per unit length of groundwater from the left bank of the river to the riverbed during the dry season, or the reverse recharge per unit length of the riverbed to the groundwater low trough on the left bank of the river, m 2 / s; q2 is the recharge per unit length of the groundwater on the right bank of the river during the dry season from the riverbed to the riverbed per unit length, or the reverse recharge per unit length from the riverbed to the groundwater low trough on the right bank of the river. The calculation process is the same as q1, m 2 / s; L is the length from the dam site to the calculated section, m; K2 is the permeability coefficient of the slope rock and soil, m / s; h1 is the height difference between the relative impermeable layer and the stable water level of the riverside slope in the dry season or the stable water level of the groundwater low trough, m; h2 is the height difference between the relative impermeable layer and the water level of the riverbed in the dry season, m; H1 is the stable water level of the riverside slope in the dry season or the stable water level of the groundwater low trough, m; H2 is the water level of the riverbed in the dry season, m; l is the distance from the riverbed water edge to the stable water level line of the riverside slope in the dry season or the stable water level line of the groundwater low trough, m.

7. The method for calculating ecological water demand considering habitats of dominant species and groundwater recharge according to claim 1, characterized in that: Step (4) Input the ecological flow velocity and ecological water depth of the dominant species obtained in steps (1) and (2) into the ecological hydraulic radius method, and add the groundwater recharge demand of the river profile obtained in step (3) to obtain the ecological water demand, and the formula is as follows: R e =n 3 / 2 ×V e 3 / 2 ×J 3 / 4 Among them, Q e is the ecological water demand, m 3 / s; n is the roughness of the river channel; R e is the hydraulic radius of the river, m; A e is the cross-sectional area of ​​water flow, m 2 ; J is hydraulic slope; V e is the ecological flow velocity, m / s.

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