A method for calculating water replenishment in blue-green space of river and lake ecology based on multidisciplinary cross-disciplinary theory

Abstract

The present invention relates to the field of hydrology and water resources technology, and specifically to a method for calculating the water replenishment of the blue-green space of river and lake ecology based on multidisciplinary cross-theory. By integrating the theoretical foundations of hydrology, soil hydrodynamics, water supply and drainage and other disciplines, and using statistical methods to eliminate errors and uncertainties, the method can accurately determine the seepage loss of urban rivers and lakes, providing scientific, quantitative and precise scientific support for managers and decision makers, significantly reducing water resource management costs, improving water resource utilization efficiency and promoting the rational allocation of water resources.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrology and water resources, and in particular to a method for calculating water replenishment in the blue-green space of river and lake ecology based on multidisciplinary cross-theory. Background Art

[0002] Urban river and lake systems are the cornerstone of urban water security and a crucial component of the aquatic ecosystem. To maintain sufficient surface area, appropriate flow, excellent water quality, and a diverse ecosystem, urban rivers and lakes must first meet their ecological water needs. However, due to the unique timing of flood seasons, water resources vary widely. To maintain year-round water availability and beautiful landscapes in urban rivers and lakes, significant water replenishment is required, at least during the dry season. This requires precise calculation of the ecological water needs of urban rivers and lakes.

[0003] The ecological water demand of urban rivers and lakes generally includes three aspects: evaporation and leakage loss, water source renewal water demand and riverside ecological landscape water demand. The calculation methods of water surface evaporation are relatively mature. One type is the conversion from evaporation pan to water surface evaporation, and the other is the calculation of water surface evaporation based on potential evaporation. The main difficulty in leakage is that due to the high heterogeneity of soil, the soil properties in different regions and depths vary greatly. The leakage observation based on the point scale is difficult to expand to the regional scale, resulting in the difficulty in estimating the river leakage loss. From the perspective of water source renewal water demand, the calculation of water surface evaporation is relatively mature. One type is the conversion from evaporation pan to water surface evaporation, and the other type is the calculation of water surface evaporation based on potential evaporation. The main difficulty in leakage is that due to the high heterogeneity of soil, the soil properties in different regions and depths vary greatly. The leakage observation based on the point scale is difficult to expand to the regional scale, which makes it difficult to estimate the river leakage loss. From the perspective of quantity, fresh water sources are added to form a certain water dynamics with the goal of increasing dissolved oxygen in water bodies, improving the self-purification capacity of water bodies, and inhibiting algae outbreaks. There is currently no consensus on the calculation method for this part of the quantity; from the perspective of the water demand of the riparian zone ecological landscape, the banks of urban rivers and lakes are generally ornamental vegetation, which generally requires irrigation to supplement water shortages. The calculation method of the ecological water demand of vegetation of a single species is relatively mature, but the calculation of the water demand of regional riparian zone vegetation landscape considering the growth needs of different types of vegetation still requires a complete set of calculation methods.

[0004] To address the above issues, existing technologies are subject to a range of uncertainties during actual observations, including wind and waves, instrument signals and accuracy, the technical level of instrument monitoring personnel, and on-site water extraction and irrigation. Even with a year of continuous observation, it is difficult to obtain relatively stable and reliable seepage data. Under actual working conditions, soil infiltration is divided into vertical seepage and lateral seepage. Existing soil column experiments also struggle to reflect the true state of regional soil infiltration. Furthermore, the "electricity-to-water" approach presents technical and economic challenges. Different water source and receiving area water levels require different pumping heads, resulting in different operating power levels for the pump station. This means that the same amount of electricity may not result in the same amount of water. Furthermore, electricity prices vary, with peak and valley prices, and electricity rates applied at different times of day can also introduce uncertainty when deriving seepage losses from pump station electricity consumption.

[0005] Therefore, when calculating the seepage loss of urban rivers and lakes from the perspectives of different disciplines such as hydrology, soil hydrodynamics, and water supply and drainage, there are certain disciplinary theoretical foundations and practical uncertainties. In addition, the amount of water resources required for ecological water replenishment throughout the year directly affects the urban river and lake operation and maintenance expenses (water and electricity charges). When the observation error at a point is used to calculate the overall water account of the regional river and lake system, it will produce an error amplification effect.

[0006] Therefore, it is necessary to design a method for calculating the water replenishment of the blue-green space of river and lake ecology based on multidisciplinary cross-theory, integrating the theoretical basis of hydrology, soil hydrodynamics, water supply and drainage and other disciplines, integrating the existing theoretical advantages, making full use of various types of observation data and extracting effective information from them, and using statistical methods to eliminate uncertainty, so as to achieve the purpose of accurate calculation, provide scientific, quantitative and precise scientific support for managers and decision makers, significantly reduce the cost of water resource management, improve the efficiency of water resource utilization, and promote the rational allocation of water resources. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a method for calculating the water replenishment of the blue-green space of river and lake ecology based on multidisciplinary cross-theory. It integrates the theoretical basis of hydrology, soil hydrodynamics, water supply and drainage and other disciplines, integrates the advantages of existing theories, makes full use of various types of observation data and extracts effective information from them, and uses statistical methods to eliminate uncertainty, so as to achieve the purpose of accurate calculation, provide scientific, quantitative and precise scientific support for managers and decision makers, significantly reduce the cost of water resource management, improve the efficiency of water resource utilization, and promote the rational allocation of water resources.

[0008] In order to achieve the above objectives, the present invention provides a method for calculating the water replenishment amount of the blue-green space of river and lake ecology based on multidisciplinary cross-theory:

[0009] The blue-green space includes the blue space of rivers and lakes and the green space within the blue line of the river; the water replenishment calculation includes the calculation of the water demand for evaporation and leakage of the blue space, the calculation of the water demand for water source renewal in the blue space, and the calculation of the water demand for irrigation in the green space.

[0010] Among them, the calculation of the evaporation and leakage water demand of the blue space is selected from any one of the evaporation and leakage water demand calculation based on historical literature research, the evaporation and leakage water demand calculation based on in-situ observation tests, and the evaporation and leakage water demand calculation based on the power consumption of the water replenishment pump station.

[0011] S1, the blue space in the blue-green space refers to the space with water volume in rivers and lakes, specifically:

[0012] The amount of water lost due to evaporation and seepage is used to maintain the water level of rivers and lakes at normal levels all year round and to maintain the water area; the amount of water retained for water source renewal means that the water quality meets the functional requirements of the water body while maintaining the flow of the water body;

[0013] The calculation of evaporation and leakage water demand based on historical literature research is as follows:

[0014] Calculation of water surface evaporation loss:

[0015] When the precipitation is greater than the evaporation of the water surface, the evaporation water requirement of the water surface is considered to be 0;

[0016] When the precipitation is less than the evaporation of the water surface, the calculation formula is:

[0017] Q 蒸发 =(EP)×A÷10;

[0018] Among them, Q 蒸发 The water demand for evaporation from the water surface, unit: 10,000 m 3 ; E is the evaporation of water surface, unit: mm; P is the precipitation, unit: mm; A is the water surface area of ​​the river, unit: km 2 ;

[0019] in, Water surface evaporation E Calculated based on the city's average annual precipitation over many years and the water surface evaporation conversion coefficient;

[0020] Calculation of water demand due to leakage loss:

[0021] The empirical formula was confirmed by comprehensive analysis of groundwater dynamics, river infiltration simulation experiments, and empirical formulas. The empirical formula is:

[0022] Q 渗漏 =K 渗漏 ×A×100;

[0023] where Q 渗漏 Leakage water demand, unit: 10,000 m 3 ;K 渗漏 is the river leakage coefficient, unit: m / year; A is the river surface area, unit: km 2 ;

[0024] where K 渗漏 Based on the monitoring of river infiltration simulation experiments, or the hydrogeological survey results of regional geotechnical engineering investigation reports, as well as the relevant literature survey of the basin where the study area is located;

[0025] The K 渗漏 In typical plain river network areas, it is 1.93 mm / d, or 0.7 m / a.

[0026] When the surface layer below the ground is silty clay, silt or fine sand, the K 渗漏 They are 0.1mm / d~5.2mm / d, 5.2mm / d~52mm / d, and 52mm / d~104mm / d respectively.

[0027] The calculation of evaporation and leakage water demand based on in-situ observation test is as follows:

[0028] Evaporation leakage calculation:

[0029] Referring to the calculation formula of evaporation and leakage water demand, under the premise of knowing the evaporation and leakage capacity of the river, the calculation formula of the evaporation and leakage loss water demand of the water system can be simplified to: Q 蒸发渗漏 =K 蒸发渗漏 ×A×100; where Q 蒸发渗漏 The water loss required by evaporation and leakage, unit: 10,000 m 3 ;K 蒸发渗漏 is the evaporation leakage coefficient, unit: m / year; A is the river surface area, unit: km 2 ;

[0030] Evaporation leakage coefficient K 蒸发渗漏 The determination method is:

[0031] Taking the evaporation and leakage law of the target water system as the goal, the data of the in-situ observation time, field condition control, observation point, index, frequency and instrument use are recorded to obtain the data; it is necessary to eliminate the abnormal fluctuation data and the external interference data, and obtain the evaporation and leakage of different river sections in the observation experiment sequence. The arithmetic mean is taken as the average evaporation and leakage, and the minimum and maximum values ​​are taken as the range of evaporation and leakage values. The specific calculation method is as follows:

[0032] Calculate the evaporation leakage coefficient K for each observation 蒸发渗漏 :

[0033] Where: ΔH i is the observed change value of the target water level during the i-th in-situ observation period, unit: m; T i is the duration of the i-th in-situ observation, in s;

[0034] Calculate the average value of the evaporation leakage coefficient Where n is the number of valid observations; the sample standard deviation T is calculated using the Bessel formula:

[0035]

[0036] Determine and remove outliers:

[0037] use As a judgment criterion, if a K 蒸发渗漏 satisfy It is considered an outlier and should be eliminated. The number of samples after eliminating the outlier is calculated as n′;

[0038] Recalculate the average evaporation leakage coefficient K 蒸发渗漏 :

[0039]

[0040] Among them, K 蒸发渗漏 ′ is the evaporation leakage coefficient of each observation after removing abnormal values;

[0041] Determine the range of evaporation leakage [K min , K max ]:

[0042] From the data set after removing outliers, take the minimum value K min and the maximum value K max As the value range of evaporation leakage.

[0043] Evaporation leakage coefficient K 蒸发渗漏 The correction method needs to take into account evaporation, leakage and groundwater level rise, and the correction methods are:

[0044] Method 2: Evaporation: The annual distribution pattern of river evaporation is calculated based on the monthly water surface evaporation conversion coefficient. The specific calculation method is as follows:

[0045] Collect monthly water surface evaporation data for many years:

[0046] Obtain the multi-year average monthly evaporation data E for the target water system area i , where i = 1, 2, ..., 12 represents the month;

[0047] Calculate the monthly evaporation conversion factor:

[0048] Calculate the total evaporation for the whole year:

[0049] Calculate the evaporation conversion factor k for each month 蒸发,i :

[0050]

[0051] Corrected evaporation during the observation period:

[0052] The evaporation during the observation period is corrected according to the conversion coefficient corresponding to the observation month:

[0053]

[0054] Where: n is the number of observations; E j is the evaporation amount observed at the jth time; m j is the month corresponding to the j-th observation;

[0055] Method 2: Leakage: The annual distribution pattern of river leakage is estimated based on the rainfall distribution pattern and groundwater level in the area;

[0056] Collect monthly rainfall and groundwater level data:

[0057] Get the multi-year average monthly rainfall P of the target area i and monthly average groundwater depth G i , where i is the month;

[0058] Calculate the monthly leakage conversion coefficient:

[0059] According to rainfall and groundwater level, establish the leakage conversion coefficient k for each month 渗漏,i The empirical formula of linear regression is used as an example.

[0060] k 渗漏,i =a×P i +b×G i +c;

[0061] Among them, a, b, and c are unknown coefficients, which are determined by fitting historical data;

[0062] Corrected leakage during the observation period:

[0063] The leakage volume during the observation period is corrected according to the conversion coefficient corresponding to the observation month:

[0064] L=L 观测 ×k 渗漏,i ;

[0065] Where: L 观测 is the observed leakage;

[0066] Method 3: Coefficient correction for future groundwater level rise background:

[0067] Based on the monitoring data of shallow groundwater depth in the target area, the groundwater level changes are analyzed, and the future groundwater evolution trend is predicted and reasonable corrections are made. By collecting the groundwater level monitoring data of the target area over the years, the groundwater level change curve is drawn, and its long-term change trend and periodicity are analyzed. The linear fitting method is used to determine the estimated value of the future groundwater level.

[0068] The specific calculation of water demand due to evaporation and leakage based on the power consumption of the water replenishment pump station is as follows:

[0069] A liquid level meter is installed between the pumps to monitor the water level in the pump station. The amount of replenishment water is determined by the accumulated water volume measured by the electromagnetic flow meter installed on the outlet pipe. The water consumption of other pump stations is excluded and converted into the power consumption of the pump station, and the calculation is carried out in the form of electricity to water conversion.

[0070] The calculation of the irrigation water demand of green space in the blue-green space is the irrigation demand to maintain the ecological life needs of grassland and forest bank vegetation within the width of the river blue line. It is calculated using the irrigation quota method. The formula is:

[0071] Q 绿化 =C 绿化 ×S×100;

[0072] where Q 绿化 Green irrigation water demand, unit: 10,000 m 3 ; C 绿化 Greening irrigation quota, unit: m 3 / (m 2 a) 0.3~0.9m 3 / (m 2 a); S is the green area on both sides of the river, unit: km 2 ;

[0073] The irrigation quota for green space is formulated according to the "Water Use Quota" standard. Generally speaking, the irrigation quota for green space is 0.6m per year. 3 / (m 2 a);

[0074] The irrigation times of the green space are specifically set as follows:

[0075] The green space is irrigated 10 times per month from June to September, 6 times per month in April, May and October, and 3 times per month in February, March and November. January and December are frozen periods and no irrigation is required. Based on the above irrigation cycles, the annual irrigation frequency is 67 times.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] The present invention integrates the theoretical foundations of hydrology, soil hydrodynamics, water supply and drainage and other disciplines, integrates the existing theoretical advantages, makes full use of various types of observation data and extracts effective information from them, and uses statistical methods to eliminate uncertainty, thereby achieving the purpose of accurate accounting, providing scientific, quantitative and precise scientific support for managers and decision makers, significantly reducing the cost of water resource management, improving the efficiency of water resource utilization, and promoting the rational allocation of water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 This is a schematic diagram of the ecological water demand accounting framework for the blue-green space of urban river and lake systems in the present invention. DETAILED DESCRIPTION

[0079] The present invention will now be further described with reference to the accompanying drawings.

[0080] See also Figure 1The present invention provides a method for calculating the water replenishment of the blue-green space of river and lake ecology based on multidisciplinary cross-theory. The blue-green space of urban river and lake water systems mainly includes the river and lake water space and the green space within the blue line of the river.

[0081] like Figure 1 As shown, ensuring blue space essentially means having sufficient water. First, it compensates for losses due to evaporation and seepage, maintaining a constant water level and a certain surface area throughout the year. Second, it leaves enough water for water source renewal, allowing the river to flow while ensuring water quality meets functional requirements. Ensuring green space essentially means maintaining the basic vital needs of shoreline vegetation, such as grasslands and trees, within the ideal blue line width of the river.

[0082] (1) Water demand for evaporation and leakage in blue space

[0083] Estimating water consumption from evaporation and seepage in river and lake systems is complex due to variations in soil compaction, groundwater depth, and the health of aquatic ecosystems. This study estimates water demand for evaporation and seepage in the blue space of a water system based on three methods: historical literature surveys, in-situ observations of evaporation and seepage in the water system, and pumping station water replenishment scheduling data.

[0084] 1) Calculation of water demand due to evaporation and leakage based on historical literature research

[0085] Calculation of water surface evaporation loss: Part of the river's water demand comes from replenishing the evaporation loss of the water surface. The amount of evaporation from the water surface is not only related to the water surface area and temperature, but is also directly affected by precipitation. When the precipitation is small and insufficient to replenish the evaporation consumption, the excess net water consumed by evaporation is provided by the river itself, which is also called the water surface evaporation demand. When the precipitation is greater than the evaporation of the water surface, the evaporation demand of the water surface is considered to be 0, and its calculation formula is:

[0086] Q 蒸发 =(EP)×A÷10;

[0087] Where: Q 蒸发 —Water demand for evaporation from water surface, 10,000 / m 3 ; E—water surface evaporation, mm; P—precipitation, mm; A—river surface area, km 2 .

[0088] Generally speaking, water surface evaporation is estimated based on the multi-year average (1956-2016) annual precipitation in typical urban areas and the water surface evaporation conversion coefficient.

[0089] Calculation of water demand for leakage loss: When the river water level is higher than the groundwater level on both sides, the river water level replenishes the groundwater in the form of seepage under the action of gravity, which is river leakage.

[0090] The seepage water requirement of a river is related to the soil permeability coefficient of the riverbed and the river's hydraulic gradient, and can be calculated using Darcy's equation. Considering that the soil permeability coefficient under natural conditions is affected by multiple factors such as water level, soil type, and river morphology, it is generally determined using methods such as groundwater dynamics or field experiments using river channel permeability simulation. The river channel seepage loss can be calculated using the empirical formula:

[0091] Q 渗漏 =K 渗漏 ×A×100;

[0092] Where: Q 渗漏 : Leakage water demand, 10,000 m 3 ;K 渗漏 : River leakage coefficient, m / year; A: River surface area, km 2 .

[0093] The value of the river channel leakage coefficient is related to the river's location and its seepage reduction efforts. The geological lithology of the riverbed determines its infiltration capacity. When the riverbed is sandy, the river seepage is high; when the riverbed is clayey, the river seepage is low. The permeability coefficient can generally be obtained based on the hydrogeological survey results in the regional geotechnical engineering investigation report, or by consulting relevant literature on the study area, its adjacent areas, or its basin. The subsurface layer is primarily composed of silty clay, silt, and fine silt sand, with corresponding permeability coefficients ranging from 0.1 mm / d to 5.2 mm / d for silty clay, 5.2 mm / d to 52 mm / d for silt, and 52 mm / d to 104 mm / d for fine silt sand.

[0094] The leakage coefficient of rivers in plain river network areas is usually taken as 1.93mm / d, that is, 0.7m / a. During the water resources survey and evaluation in Tianjin, the flow measurement data of upstream and downstream sections of the river during the non-agricultural irrigation period and the Yellow River diversion period were used to analyze and calculate the river leakage intensity. The leakage coefficient is generally 1mm / d to 2.6mm / d, that is, 0.365m / a to 0.949m / a. The soil layer in the riverbed of the Yongding River in Tianjin is extremely micro-permeable, and the groundwater depth is about 2.0m. Referring to the experimental data of nearby rivers, the leakage coefficient of the Yongding River is about 2.0mm / d, which is equivalent to 0.73m / a. The theoretical leakage coefficient of the bentonite waterproofing blanket process is 6.6×10 -7 cm / s, which is 0.21m / a.

[0095] 2) Calculation of evaporation and leakage water demand based on in-situ observation tests

[0096] Calculation of evaporation and leakage: The in-situ observation experiment measures the total amount of evaporation and leakage. Therefore, referring to the calculation formula of evaporation and leakage water requirements, under the premise of knowing the evaporation and leakage capacity of the river channel, the calculation formula of the water system evaporation and leakage loss can be simplified to:

[0097] Q 蒸发渗漏 =K 蒸发渗漏 ×A×100;

[0098] Where: Q 蒸发渗漏 : Water loss due to evaporation and leakage, 10,000 m 3 ;K 蒸发渗漏 : Evaporation leakage coefficient, m / year; A: River surface area, km 2 .

[0099] Determination method of evaporation and leakage coefficient based on in-situ observation: The prototype observation test aims to study the evaporation and leakage laws of the target water system. By observing water level data, the evaporation and leakage conditions of the water system are analyzed to provide a basis for calculating the water demand for evaporation and leakage of the water system.

[0100] When the water system is not replenished, the time series of evaporation and leakage analysis for each river section varies due to the subsequent opening time of the replenishment pump station or the control culvert gate.

[0101] Data showing abnormal fluctuations were discarded. The initial water level at the first point along the recharge path was the highest, and the initial water level at points along the path decreased. Without recharge, the river water level at each monitoring point showed an overall steady decrease due to evaporation and seepage. Minor fluctuations in the data chain at some points were primarily due to human observation errors.

[0102] Eliminate any external interference that may affect the observation experiment, such as strong winds, upstream water replenishment, irrigation water withdrawal, etc. It can be assumed that the water level changes in each river channel are caused by evaporation and leakage.

[0103] Evaporation and seepage were calculated based on water level changes during the observation period for each river section. After eliminating invalid data, the evaporation and seepage values ​​for different river sections within a given observation experiment sequence were obtained. Evaporation and seepage data at different locations may vary, so the arithmetic mean was used as the average evaporation and seepage value, and the minimum and maximum values ​​were used as the range of evaporation and seepage values.

[0104] Correction Method for Evaporation and Leakage Coefficients Considering Observation Period and Groundwater Level Changes: Based on evaporation and leakage tests, evaporation and leakage coefficients were calculated for different river sections. Considering that river evaporation and leakage coefficients are related to observation period, river construction and operation status, and groundwater level, to obtain a reasonable evaporation and leakage coefficient, the measured evaporation and leakage coefficients should be corrected based on actual conditions. For example, due to the recent implementation of ecological water replenishment and groundwater pressure extraction in the North China Plain, groundwater levels have been rising, and the impact of groundwater level changes on river leakage should be considered.

[0105] Coefficient correction considering the influence of observation period:

[0106] Affected by factors such as annual rainfall, temperature and groundwater, evaporation and leakage have seasonal variability. The data observed in a certain season are significantly different from the average evaporation and leakage coefficient of the whole year, and the evaporation and leakage coefficient needs to be corrected.

[0107] ① Evaporation: The annual distribution pattern of river evaporation is calculated based on the monthly water surface evaporation conversion coefficient.

[0108] ② Leakage: The annual distribution of river leakage is closely related to regional rainfall patterns and groundwater levels. In areas with uneven rainfall distribution, river leakage will also exhibit uneven distribution throughout the year. During the dry season, when groundwater levels are relatively low and river flows are generally relatively low, river leakage will also be relatively low. During the wet season, when flows gradually increase, leakage also increases. However, as groundwater gradually replenishes and groundwater levels rise on both sides of the river, river leakage will gradually decrease.

[0109] Coefficient correction considering the background of future groundwater level rise:

[0110] When the groundwater level is buried deep, the seepage can infiltrate freely and the leakage volume is large; when the groundwater level is buried shallow, the groundwater level supports the infiltration and the leakage volume decreases. The leakage volume is linearly related to the leakage intensity.

[0111] Consider the impacts of groundwater pressure extraction and river ecological recharge in northern China. Based on monitoring data on shallow groundwater depth in the study area, analyze groundwater level changes and predict future groundwater evolution. It can be assumed that the leakage coefficient observed in this study is greater than the leakage coefficient after groundwater recovery. When predicting future leakage coefficients, it is necessary to make reasonable corrections based on future groundwater level changes.

[0112] 3) Calculation of evaporation and leakage water demand based on the power consumption of the water replenishment pump station

[0113] For river and lake systems in northern cities, ecological water replenishment is usually carried out through gates or pumping stations to maintain scenic water areas. For river and lake systems that use pumping stations for water replenishment, the power consumption of the pumping stations is one of the important bases for water consumption calculation. When using the method of converting electricity to water to calculate evaporation and leakage, it is important to consider the elimination of other influencing factors, such as irrigation water intake. For example, if a water replenishment channel uses three pumps, and the design flow rate of each pump is Q = 1800m 3 / h, with a designed head of H = 8m and a power of N = 55kW. Water is supplied via two DN800 pressure pipes, with two electromagnetic flowmeters installed on the outlet pipes. An ultrasonic level gauge is installed in the pump room. The pumps are manually started and stopped based on water conditions. If the water level in the pumping station falls below 5.5m, the pumps are forced to stop. All supply water is pumped through the pumping station, so the amount of supply water can be determined by the accumulated water volume measured by the electromagnetic flowmeter.

[0114] (2) Water demand for blue space water source renewal

[0115] For rivers controlled by dams and sluice gates, water source renewal is often necessary to maintain the self-purification capacity and hydrodynamics of the river. Drawing on the calculation method for lake water source renewal, the water requirement is determined based on a set number of water source renewals and the river channel storage capacity, taking into account multiple factors such as the importance of the river in the starting area and the availability of replenishment water sources.

[0116] Q 水源更新 =K 水源更新 ×q;

[0117] Where: Q 水源更新 : Water source renewal water demand, 10,000 m 3 ;K 水源更新 : Water source renewal times, times / year; q: Storage capacity of the water source renewal river, 10,000 m 3 .

[0118] The water source renewal cycle or frequency should be maintained within a reasonable range. If the cycle is too short, sediment nitrogen and phosphorus are easily released, frequent water replacement is detrimental to biological growth, and the interception of non-point source pollutants and water purification services are reduced. If the cycle is too long, it will not be conducive to increased DO concentration in the water and the growth of organisms that are more adaptable to dynamic disturbances, and it may easily cause eutrophication. Under natural conditions, the river water renewal cycle is 16 days, so the water source renewal frequency is considered to be twice a month.

[0119] Considering that the primary long-term water source for urban river replenishment is recycled water, and that summer temperatures are high and algae outbreaks are prone, the retention time of recycled water should not be too long. Therefore, in summer, internal water circulation within the river should be used to increase water mobility, ensure the rapid inflow and outflow of recycled water, shorten retention time, and prevent algae outbreaks and water quality deterioration. Due to the low temperatures in winter (December to February) (the average temperature from 1961 to 2005 was -1.7°C), many rivers are frozen, so water source renewal is not carried out. In summary, the long-term water source renewal period is spring, summer, and autumn, with an update frequency of twice a month, and a minimum of 18 water source renewals per year.

[0120] (3) Green space irrigation water demand

[0121] The calculation scope of green space water demand this time is only the green space within the blue line on both sides of the river and lake systems in northern cities. The water demand of other park green spaces is not within this scope.

[0122] The water demand for greening irrigation is calculated using the quota method. The calculation formula is as follows: Q 绿化 =C 绿化 ×S×100

[0123] Where: Q 绿化 The water demand for greening irrigation, 10,000 m 3 ; C 绿化is the greening irrigation quota, m 3 / (m 2 a) Generally 0.3 to 0.9 m 3 / (m 2 a); S is the green area on both sides of the river, km 2 .in:

[0124] Greening irrigation area: The green area on both sides of the river is determined based on the width of the blue line of the river.

[0125] Comprehensive irrigation quota: According to the provincial local standard "Water Use Quota" (DB**) (each province has its own local water use quota standard), generally speaking, the annual comprehensive irrigation quota for park green space is 0.6m 3 / (m 2 a).

[0126] Green space irrigation frequency: determined based on comprehensive analysis of local actual conditions. For example, in a city on the North China Plain, green space is irrigated 10 times per month from June to September, 6 times per month in April, May, and October, and 3 times per month in February, March, and November. January and December are frozen periods and no irrigation is required. Based on the above irrigation cycles, the annual irrigation frequency is 67 times.

[0127] The above are merely preferred embodiments of the present invention and are intended to help understand the method and core concept of this application. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention fall within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

[0128] The present invention solves the existing problems encountered in actual working conditions and applications, such as the difficulty in expanding and estimating point-scale seepage observations due to the high degree of soil heterogeneity and large differences in properties, which are encountered in the existing technology based on three aspects: evaporation and seepage loss, water source renewal requirements, and riparian ecological landscape requirements. These problems also include the inconsistency in calculation methods for increasing dissolved oxygen in water, water self-purification, and algae inhibition, the difficulty in obtaining stable and reliable data from evaporation observations, the lack of true vertical and lateral seepage data from soil column experiments, and the uncertainty of costs caused by converting electricity to water. By integrating the theoretical foundations of hydrology, soil hydrodynamics, water supply and drainage, and using statistical methods to eliminate errors and uncertainties, the method can accurately determine the seepage loss of urban rivers and lakes, providing scientific, quantitative, and precise scientific support for managers and decision makers, significantly reducing water resource management costs, improving water resource utilization efficiency, and promoting the rational allocation of water resources.

Claims

1. A method for calculating water replenishment in the blue-green space of river and lake ecology based on multidisciplinary cross-disciplinary theory, characterized by: The blue-green space includes the blue space of rivers and lakes and the green space within the blue line of the river; the water replenishment calculation includes the calculation of the water demand for evaporation and leakage of the blue space, the calculation of the water demand for water source renewal in the blue space, and the calculation of the water demand for irrigation of the green space; The calculation of the evaporation and leakage water demand of the blue space is selected from any one of the following: the evaporation and leakage water demand calculation based on historical literature research, the evaporation and leakage water demand calculation based on in-situ observation tests, and the evaporation and leakage water demand calculation based on the power consumption of the water replenishment pump station; The calculation of evaporation and leakage water demand based on historical literature research is as follows: Calculation of water surface evaporation loss: When the precipitation is greater than the evaporation of the water surface, the evaporation water requirement of the water surface is considered to be 0; When the precipitation is less than the evaporation of the water surface, the calculation formula is: Q 蒸发 =(E-P)×A÷10; Among them, Q 蒸发 The water demand for evaporation from the water surface, unit: 10,000 m 3 ; E is the evaporation of water surface, unit: mm; P is the precipitation, unit: mm; A is the water surface area of ​​the river, unit: km 2 ; Among them, the water surface evaporation E is calculated based on the city’s average annual precipitation over many years and the water surface evaporation conversion coefficient; Calculation of water demand due to leakage loss: The empirical formula was confirmed by comprehensive analysis of groundwater dynamics, river infiltration simulation experiments, and empirical formulas. The empirical formula is: Q 渗漏 =K 渗漏 ×A×100; where Q 渗漏 Leakage water demand, unit: 10,000 m 3 ;K 渗漏 is the river leakage coefficient, unit: m / year; A is the river surface area, unit: km 2 ; where K 渗漏 Based on the monitoring of river infiltration simulation experiments, or the hydrogeological survey results of regional geotechnical engineering investigation reports, as well as the relevant literature survey of the basin where the study area is located; The K 渗漏 In typical plain river network areas, it is 1.93 mm / d, or 0.7 m / a; The calculation of the evaporation and leakage water demand based on the in-situ observation test is specifically as follows: Evaporation leakage calculation: Referring to the calculation formula of evaporation and leakage water demand, under the premise of knowing the evaporation and leakage capacity of the river, the calculation formula of the evaporation and leakage loss water demand of the water system can be simplified to: Q 蒸发渗漏 =K 蒸发渗漏 ×A×100; where Q 蒸发渗漏 The water loss required by evaporation and leakage, unit: 10,000 m 3 ;K 蒸发渗漏 is the evaporation leakage coefficient, unit: m / year; A is the river surface area, unit: km 2 ; Evaporation leakage coefficient K 蒸发渗漏 The determination method is: Taking the evaporation and leakage law of the target water system as the goal, the data of the in-situ observation time, field condition control, observation point, index, frequency and instrument use are recorded to obtain the data; it is necessary to eliminate the abnormal fluctuation data and exclude the external interference data, and obtain the evaporation and leakage of different river sections in the observation experiment sequence. The arithmetic mean is taken as the average evaporation and leakage, and the minimum and maximum values ​​are taken as the range of evaporation and leakage values. The specific calculation method is as follows: Calculate the evaporation leakage coefficient K for each observation 蒸发渗漏 : Where: ΔH i is the observed change value of the target water level during the i-th in-situ observation period, unit: m; T i is the duration of the i-th in-situ observation, in s; Calculate the average value of the evaporation leakage coefficient Where n is the number of valid observations; Use Bessel's formula to calculate the sample standard deviation T: Determine and remove outliers: use As a judgment criterion, if a K 蒸发渗漏 satisfy It is considered an outlier and should be eliminated. The number of samples after eliminating the outlier is calculated as n′; Recalculate the average evaporation leakage coefficient K 蒸发渗漏 : Among them, K 蒸发渗漏 ′ is the evaporation leakage coefficient of each observation after removing abnormal values; Determine the range of evaporation leakage [K min , K max ]: From the data set after removing outliers, take the minimum value K min and the maximum value K max As the value range of evaporation leakage; The evaporation leakage coefficient K 蒸发渗漏 The correction methods are: Method 1: Evaporation: The annual distribution pattern of river evaporation is calculated based on the monthly water surface evaporation conversion coefficient. The specific calculation method is as follows: Collect monthly water surface evaporation data for many years: Obtain the multi-year average monthly evaporation data E for the target water system area i , where i = 1, 2, ..., 12 represents the month; calculate the monthly evaporation conversion coefficient: Calculate the total evaporation for the whole year: Calculate the evaporation conversion factor k for each month 蒸发,i : Corrected evaporation during the observation period: The evaporation during the observation period is corrected according to the conversion coefficient corresponding to the observation month: Where: n is the number of observations; E j is the evaporation amount of the jth observation; m j is the month corresponding to the j-th observation; Method 2: Leakage: The annual distribution pattern of river leakage is estimated based on the rainfall distribution pattern and groundwater level in the area; Collect monthly rainfall and groundwater level data: Get the multi-year average monthly rainfall P of the target area i and monthly average groundwater depth G i , where i is the month; Calculate the monthly leakage conversion coefficient: According to rainfall and groundwater level, establish the leakage conversion coefficient k for each month 渗漏,i The empirical formula for linear regression is: k 渗漏,i =a×P i +b×G i +c; Among them, a, b, and c are unknown coefficients, which are determined by fitting historical data; Corrected leakage during the observation period: The leakage volume during the observation period is corrected according to the conversion coefficient corresponding to the observation month: L=L 观测 ×k 渗漏,i ; Where: L 观测 is the observed leakage volume; Method 3: Coefficient correction for future groundwater level rise background: Based on the monitoring data of shallow groundwater depth in the target area, the groundwater level changes are analyzed, and the future groundwater evolution trend is predicted and reasonable corrections are made. By collecting the groundwater level monitoring data of the target area over the years, the groundwater level change curve is drawn, and its long-term change trend and periodicity are analyzed. The linear fitting method is used to determine the estimated value of the future groundwater level.

2. The method for calculating water replenishment of blue-green space of river and lake ecology based on multidisciplinary cross-theory according to claim 1 is characterized in that: When the surface layer below the ground is silty clay, silt or fine sand, the K 渗漏 They are 0.1mm / d~5.2mm / d, 5.2mm / d~52mm / d, and 52mm / d~104mm / d respectively.

3. The method for calculating water replenishment of blue-green space of river and lake ecology based on multidisciplinary cross-theory according to claim 1, It is characterized by: The calculation of the evaporation and leakage water demand based on the power consumption of the water replenishment pump station is specifically as follows: A liquid level meter is installed between the pumps to monitor the water level in the pump station. The amount of replenishment water is determined by the accumulated water volume measured by the electromagnetic flow meter installed on the outlet pipe. The water consumption of other pump stations is excluded and converted into the power consumption of the pump station, which is calculated in the form of electricity to water.

4. The method for calculating water replenishment of river and lake ecological blue-green space based on multidisciplinary cross-theory according to claim 1 is characterized in that The calculation of the irrigation water demand for green space in the blue-green space is the irrigation demand to maintain the ecological life needs of grassland and forest bank vegetation within the width of the river blue line. The irrigation quota method is used for calculation, and the formula is: Q 绿化 =C 绿化 ×S×100; where Q 绿化 Green irrigation water demand, unit: 10,000 m 3 ; C 绿化 Greening irrigation quota, unit: m 3 / (m 2 a) 0.3 to 0.9 m 3 / (m 2 a); S is the green area on both sides of the river, unit: km 2 ; The irrigation quota for green space is formulated according to the "Water Use Quota" standard. Generally speaking, the irrigation quota for green space is 0.6m per year. 3 / (m 2 a); The irrigation times of the green space are specifically set as follows: The green space is irrigated 10 times per month from June to September, 6 times per month in April, May and October, and 3 times per month in February, March and November. January and December are frozen periods and no irrigation is required. Based on the above irrigation cycles, the annual irrigation frequency is 67 times.

Images