Water ecological health assessment method based on drinking water source ground water ecological health assessment system

Abstract

The invention discloses a water ecological health assessment method based on a drinking water source water ecological health assessment system, and overcomes the defects that a water ecological environment investigation and assessment system in the prior art is not suitable, the algal toxin content is high, early-stage fish data is lacked, and drinking water source water storage branches are all secondary branch areas. The evaluation method comprises the steps that S1, a based evaluation system comprises a water quality evaluation layer, a habitat evaluation layer and a biological evaluation layer with the weights of X1, X2 and X3, the weights of the three evaluation layers are determined according to the water ecological condition of a to-be-monitored area, and X1 + X2 + X3 = 1; s2, constructing a water ecological health assessment system of the to-be-monitored area; s3, monitoring index sub-items of water ecology of the to-be-monitored area; and S4, evaluating the water ecological health of the to-be-monitored area. According to the evaluation system and method, the water quality evaluation layer, the habitat evaluation layer and the organism evaluation layer are arranged, the weight is set according to the water ecological condition of the to-be-monitored area, and the evaluation method is more scientific.

Description

Technical Field

[0001] The present invention relates to the technical field of water ecological protection, and in particular to a water ecological health assessment method based on a drinking water source water ecological health assessment system. Background Art

[0002] Water ecological assessment is an important means to measure whether the water body is healthy and the ecosystem is complete. Based on water ecological survey data, it analyzes and evaluates the ecological environment quality of water bodies from the perspective of the integrity of the water ecosystem, and then provides a reasonable basis for protecting and restoring the ecological environment and rationally utilizing natural resources, ultimately serving aquatic biodiversity, water ecological health and human health.

[0003] Among the water ecological environment assessment systems that have been made public in China: (1) In the "Technical Guidelines for Monitoring and Evaluation of Water Ecological Environment Quality of Lakes and Reservoirs (Draft for Comments)" issued by the Ministry of Ecology and Environment, biological integrity has a greater weight in the entire assessment system, but there are defects such as complex indicator calculation and reliance on the experience of assessors. (2) The "Guidelines for River and Lake Health Assessment" issued by the Ministry of Water Resources covers the scope, normative reference documents, terminology, assessment principles, work flow, assessment indicators, classification standards, indicator assessment methods and scoring standards, river and lake health survey and monitoring, scoring assessment, and river, lake (reservoir) health report preparation. The main problems are: "water" and "basin" indicators mainly consider water conservancy and hydrology, data acquisition is complex and difficult, and too complicated; biological indicators only consider benthic animals and fish resources.

[0004] In addition, various provinces and cities in China have also issued water ecological environment investigation and evaluation systems suitable for their own provinces and cities. The main reference at present is the "Technical Guidelines for Survey and Evaluation of Water Ecological Environment in Rivers, Lakes and Reservoirs (Trial)" issued by a certain province. The advantages are: (1) The water ecological health assessment ultimately forms a card-style scoring result, which is simple and clear; (2) The water ecology is divided into modules for monitoring, which is easy to operate and scientific and reasonable; (3) Some monitoring indicators can be dynamically adjusted according to the water quality of the monitored area. However, the above technical guidelines for water ecological environment investigation and evaluation have the following defects: (1) There is a lack of algae toxin indicators in the monitoring indicators, which is not suitable for areas with high algae toxin content; (2) It is not suitable for areas where early fish data are missing; (3) The water quality indicators of the tributaries entering the reservoir are stipulated as first-level tributaries, which is not suitable for areas where the tributaries entering the reservoir of drinking water sources are all second-level tributaries. Because the water quality of the tributaries entering the reservoir has a great impact on the health of the reservoir water ecology, it is necessary to consider including all unretained tributaries in the evaluation indicators. Summary of the invention

[0005] The present invention overcomes the shortcomings of the water ecological environment investigation and evaluation system in the prior art, which is not suitable for areas with high algal toxin content, missing early fish data, and all tributaries entering the drinking water source are secondary tributaries, and provides a water ecological health assessment method based on the drinking water source water ecological health assessment system.

[0006] The technical solution adopted to achieve the first invention objective of the present invention is: a water ecological health assessment method based on a drinking water source water ecological health assessment system, comprising the following steps:

[0007] S1. The water ecological health assessment system based on this water ecological health assessment method includes: water quality assessment layer, habitat assessment layer and biological assessment layer; the weights of water quality assessment layer, habitat assessment layer and biological assessment layer are X 1 , X 2 and X 3 , X 1 , X 2 and X 3 Determined according to the water ecology of the area to be monitored, X 1 +X 2 +X 3 =1;

[0008] The water quality assessment layer includes the following water quality index sub-items: water quality compliance rate, excellent surface water ratio, surface water ratio worse than Class V, and comprehensive nutrient status index;

[0009] The habitat assessment layer includes the following habitat index sub-items: lake and reservoir entrance accessibility, lakeside ecological buffer zone vegetation coverage, wetland degradation index and habitat complexity;

[0010] The biological assessment layer includes the following biological indicator sub-items: phytoplankton integrity index, benthic invertebrate integrity index, fish stock index, and changes in rare species, native species, alien species, and pollution-tolerant aquatic organisms;

[0011] The screening of indicator sub-items categories for water quality indicator sub-items, habitat indicator sub-items and biological indicator sub-items is determined based on the water ecological environment characteristics and ecological service functions of the area to be monitored.

[0012] S2. Construct a water ecological health assessment system for the area to be monitored: According to the water ecological health assessment system described in S1, determine the weights X of the water quality assessment layer, habitat assessment layer, and biological assessment layer for the water ecological health assessment of the area to be monitored. 1 , X 2 , X 3 and select water quality index sub-items, habitat index sub-items and biological index sub-items from the water quality assessment layer, habitat assessment layer and biological assessment layer respectively, which are used to characterize the water ecological environment status of the area to be monitored.

[0013] S3. Monitoring of water ecology index sub-items in the area to be monitored: According to the water quality index sub-items, habitat index sub-items and biological index sub-items selected in step S2, the water ecology in the area to be monitored is monitored and the monitoring results of each index sub-item are calculated.

[0014] S4. Water ecological health assessment of the monitored area: determine the scores of each indicator sub-item of the water ecology of the monitored area according to the monitoring results of the water quality indicator sub-items, habitat indicator sub-items and biological indicator sub-items obtained in step S3, then calculate the average scores of the indicator sub-items in the same assessment layer to obtain the scores of the three assessment layers, calculate the weighted average of the scores of the obtained assessment layers according to the weights of step S1, and obtain the final score of the water ecology of the monitored area, and obtain the water ecological health assessment level of the monitored area according to the final score.

[0015] The beneficial effects of the present invention are: (1) During the water ecological health assessment process, the water quality assessment layer, habitat assessment layer and biological assessment layer of the present invention can set appropriate weights according to the actual water ecological conditions of the area to be monitored, which is more in line with the water ecological environment of the area to be investigated.

[0016] (2) The water quality assessment layer includes an indicator sub-item for algal toxins, which is suitable for areas with more phytoplankton and higher algal toxin content;

[0017] In the biological assessment layer, the benthic invertebrate integrity index is added. Benthic organisms play a greater role in indicating the health of the water ecology of deep-water lakes and reservoirs. In addition, the fish retention index and the changes in rare species, local species, alien species, and pollution-resistant species of aquatic organisms are set up, which can be used for the water ecological environment assessment of drinking water sources in areas where early fish data is missing;

[0018] Because the water quality of tributaries entering the reservoir has a significant impact on the health of the reservoir's water ecology, it is necessary to consider including all unintercepted tributaries entering the reservoir in the assessment indicators, and the lake and reservoir entrance patency rate is added to the habitat assessment layer.

[0019] (3) The evaluation layer of the present invention sets a set of evaluation indicators, which can be adjusted according to the water ecological environment characteristics and ecological service functions of the area to be monitored, and are suitable for water ecological environment evaluation in different regions.

[0020] (4) In the drinking water source water ecological health assessment method disclosed in the present invention, the score of each evaluation indicator of each assessment layer is determined according to the monitoring calculation results, and combined with the weight of each assessment layer, the final assessment result is more objective and can provide more scientific data support for the management of drinking water sources.

[0021] The present invention is further described below in conjunction with specific implementation modes. DETAILED DESCRIPTION

[0022] The following water ecological health assessment system for drinking water sources was developed for areas where early fish data was missing, algal toxin content was high, and all tributaries entering the drinking water source were secondary tributaries. The system includes three assessment layers: water quality assessment layer, habitat assessment layer, and biological assessment layer, with weights of X, 1 , X 2 and X 3 , X 1 , X 2 and X 3 Determined according to the water ecology of the area to be monitored, X 1 +X 2 +X 3 =1.

[0023] Different indicator sub-items are set in each assessment layer. The selection of indicator sub-items is determined according to the water ecological environment characteristics and ecological service functions of the area to be monitored. The indicator sub-items of the three assessment layers are as follows:

[0024] 1. Water quality assessment layer

[0025] The water quality assessment layer includes the following water quality index sub-items: water quality compliance rate, excellent surface water ratio, surface water ratio worse than Class V and comprehensive nutrient status index. The specific calculation method and evaluation criteria are as follows.

[0026] (1.1) Water quality compliance rate (%)

[0027] The water quality compliance rate involves: pH, dissolved oxygen, ammonia nitrogen, total nitrogen, total phosphorus, permanganate index, chemical oxygen demand, five-day biochemical oxygen demand, and algal toxins MC-LR, CYN and other water quality monitoring indicators that are closely related to the health of water ecology.

[0028] The water quality compliance rate is calculated by formula (1):

[0029] Scope of evaluation: limited to survey points in major lake and reservoir waters.

[0030] Set the water quality compliance rate evaluation standards, as shown in Table 1.1-1:

[0031] Table 1.1-1 Water quality compliance rate evaluation standards and grading table

[0032]

[0033] During the water ecological environment assessment of drinking water sources, the monitored areas are divided into Class A drinking water sources and Class B drinking water sources according to water quality. Class A drinking water sources are drinking water sources that mainly use external water and are surrounded by built-up areas; Class B drinking water sources are drinking water sources that mainly use self-produced water and are located in non-built-up areas.

[0034] The water quality in the monitored area must meet the Class III surface water standard. Combined with the Class A and Class B classification standards for drinking water sources and historical water quality monitoring data, the ammonia nitrogen and chemical oxygen demand (COD) of Class B drinking water sources can be measured. Mn Higher requirements are put forward, and the qualified limit is to meet the surface water Class II standard. If one of all water quality monitoring indicators does not meet the limit requirements, the whole is considered to be substandard. According to the time series, divided into flood season and dry season, the number of surveys at each point and its compliance rate are counted. The limits that need to be followed for each indicator are shown in Table 1.1-2 (the limit values ​​of MC-LR refer to the national standard, and the limit values ​​of CYN refer to the New Zealand standard)

[0035] Table 1.1-2 Limits of water quality monitoring indicators for drinking water sources in a certain city

[0036]

[0037] (1.2) Proportion of surface water of good quality (reaching or exceeding Class III) (%)

[0038] According to the comprehensive evaluation results of water quality at the survey points, the percentage of points where the water quality of all tributaries entering the drinking water source reaches or exceeds Class III is calculated:

[0039] The good quality ratio of surface water is calculated by formula (2):

[0040] The scope of evaluation objects is: all unintercepted tributaries entering the reservoir.

[0041] The water quality index limit standards for tributaries entering the drinking water source of a certain city are shown in Table 1.2-1:

[0042] Table 1.2-1 Limits of water quality monitoring indicators for tributaries entering the drinking water source in the monitored area

[0043]

[0044] The evaluation criteria are as shown in Table 1.2-2:

[0045] Table 1.2-2 Evaluation criteria and classification of surface water quality ratio

[0046]

[0047] (1.3) Proportion of surface water of Class V (%)

[0048] According to the comprehensive evaluation results of water quality at the survey points, the percentage of survey points with water quality worse than Class V in all tributaries entering the drinking water source area to be monitored is calculated, as shown in formula (3): Scope of evaluation objects: including survey points of all tributaries entering the reservoir.

[0049] The water quality limit values ​​for Class V surface water in tributaries entering the drinking water source in Shenzhen are as follows:

[0050] Table 1.3-1 Poor V Class Limits of Water Quality Monitoring Indicators of Branches Entering the Drinking Water Source in the Areas to be Investigated

[0051]

[0052] The evaluation criteria are as shown in Table 1.3-2:

[0053] Table 1.3-2 Evaluation criteria and classification of surface water proportions in Class V

[0054]

[0055] (1.4) Total Nutritional Status Index (TLI)

[0056] The comprehensive trophic state index (TLI) is limited to the evaluation of lake and reservoir water quality indicators. The calculation method of the comprehensive trophic state index TLI is as follows:

[0057] Taking the chlorophyll a status index TLI (Chla) as the benchmark and the transparency (SD) parameter as the nutritional status index indicator, a weighted comprehensive analysis is performed with TLI. The comprehensive weighted index model is formula (4):

[0058]

[0059] In formula (4), TLI(∑) is the comprehensive weighted nutritional status index; TLI(j) is the nutritional status index of the jth parameter; W j The weight of the nutritional status index of the jth parameter, W j Calculate according to formula (5):

[0060]

[0061] In formula (5): r ij is the correlation coefficient between the jth parameter and the reference parameter chla, r of transparency (SD) ij The value is 0.83; m is the number of evaluation parameters;

[0062] TLI(SD) is calculated by formula (6):

[0063] TLI(SD)=10×(5.118-1.94lnSD) Formula (6);

[0064] In order to distinguish the water ecological function characteristics of different survey objects, the comprehensive nutrient status index needs to be normalized and calculated before evaluation. The calculation formula is formula (7):

[0065]

[0066] TLI 最大值 TLI is the maximum value of the comprehensive nutritional index among the survey points in the monitoring area. 参考 TLI is the comprehensive nutritional index value of the reference point or reference state of the lake or reservoir. i is the comprehensive nutritional index value of survey point i.

[0067] The evaluation criteria are as shown in Table 1.4-1:

[0068] Table 1.4-1 Comprehensive Nutrition Index Evaluation Standard and Grading Table

[0069]

[0070] Currently, TLI 最大值 The maximum value known in each basin is used, not the maximum value of a single point in a survey. 最大值 As shown in Table 1.4-2, according to the basin of the drinking water source area to be monitored, it is divided into three basins: GD1 basin, GD2 basin and GD3 basin, and distinguishes between the flood season and the dry season, using different TLI 最大值 Calculate indicators.

[0071] Table 1.4-2 TLI of drinking water sources in the areas to be monitored 最大值

[0072] Basin Flood season Dry season GD1 Basin 54.11 57.61 GD2 Basin 50.25 50.49 GD3 Basin 65.39 62.38

[0073] TLI 参考值 As shown in the table below, the three major basins are divided into GD1 basin, GD2 basin and GD3 basin, and the high water period and low water period are distinguished, and different TLIs are used 参考值 Calculate indicators.

[0074] Table 1.4-3 TLI of drinking water sources in Shenzhen 参考值

[0075]

[0076] 2. Habitat Assessment Layer

[0077] The habitat assessment layer includes the following habitat indicator sub-items: lake and reservoir entrance accessibility, lakeside ecological buffer zone vegetation coverage, wetland degradation index and habitat complexity. The specific calculation method and evaluation criteria are as follows.

[0078] (2.1) Lake and reservoir accessibility rate (%)

[0079] The lake-reservoir entrance patency rate is used to characterize the spatial structural connection between the ecological elements of the lake-reservoir system and the rivers entering and leaving the lake. It is evaluated based on the degree of water flow between the main rivers entering and leaving the lake and the lake and reservoir, and is calculated using formula (8):

[0080]

[0081] Only those tributaries that are completely unretained are considered as inflowing tributaries. All tributaries that are completely unretained inflowing to the reservoir in all drinking water sources in the monitored area should be regarded as first-level tributaries.

[0082] The evaluation criteria are shown in Table 2.1-1:

[0083] Table 2.1-1 Evaluation criteria and grading table for lake and reservoir entrance accessibility

[0084]

[0085] (2.2) Vegetation coverage of lakeside ecological buffer zone (%)

[0086] The larger the vegetation area of ​​the lake bank, the less susceptible the natural slope bank is to water erosion and the better the habitat integrity is. The vegetation coverage in the ecological buffer zone is used to characterize this index, and the calculation method is formula (9):

[0087]

[0088] Vegetation area is limited to the statistics of non-agricultural forest land and grassland area, and the buffer zone is defined as the range 33m inward from the coastline.

[0089] The evaluation criteria are shown in Table 2.2-1:

[0090] Table 2.2-1 Evaluation criteria and classification of vegetation coverage in lakeside ecological buffer zones

[0091]

[0092] (2.3) Wetland degradation index

[0093] Wetlands refer to shallow water areas with static or flowing water, such as natural or artificial swamps, and also include waters with a depth of no more than 6m at low tide. A large number of animals and plants live in wetland ecosystems, and many wetlands are listed as nature reserves. The wetland degradation index uses the current wetland area within the lake catchment area and the historical wetland area in 2000 (or historical data before 2000) to compare and analyze to reflect the degradation of wetlands. The calculation is as follows:

[0094]

[0095] The evaluation criteria are shown in Table 2.3-1:

[0096] Table 2.3-1 Wetland degradation index evaluation standards and grading table

[0097]

[0098] (2.4) Habitat complexity of lakeside ecological buffer zone (%)

[0099] The higher the habitat complexity of the drinking water source, the better the habitat integrity and the higher the water ecological health level. The number of microhabitat species in the ecological buffer zone is used to represent this indicator. The main microhabitats that appear within the lake buffer zone are silt, fine sand, aquatic plant growth zone, grassland and woodland. The total number of microhabitat species will be increased or decreased depending on the specific field survey results.

[0100] Habitat complexity is calculated by formula (11):

[0101]

[0102] The buffer zone of lakes and reservoirs is within 33m of the lake and reservoir shoreline.

[0103] The evaluation criteria are shown in Table 2.4-1:

[0104] Table 2.4-1 Evaluation criteria and grading table of habitat complexity of lakeside ecological buffer zone

[0105]

[0106] 3. Biological Assessment Layer

[0107] The biological assessment layer includes the following biological indicator sub-items: phytoplankton integrity index, benthic invertebrate integrity index, fish retention index and changes in rare species, local species, alien species and pollution-tolerant aquatic organisms. The specific calculation methods and evaluation criteria are as follows.

[0108] (3.1) Algal integrity index (P-IBI)

[0109] The IBI index is selected to reflect the stability of the species composition, diversity and function of the floating and attached algae communities in a region. Three parameters, namely, biological density, total number of taxa and Berger-Parker index (BP index), are selected for calculation. Among them, there is a large correlation between biological density and water pollution; the total number of taxa is the number of all species identified at each monitoring sample point, which can reflect the abundance of the community; the BP index is the dominance index, which reflects the changes in the number of populations of each species. The larger the ecological dominance index, the more uneven the distribution of species in the community, and the more prominent the status of the dominant species. The dominance of a certain algae = a certain algae density / total algae density, and the algae with a dominance of >2% are dominant species. The values ​​of these three parameters are obtained through statistical analysis after the collection and identification of aquatic organisms and quantitative analysis.

[0110] (3.1.1) The calculation method of the algae integrity index is as follows: Formula (12), (13), (14). If the calculation result is a negative value, it is taken as 0; if it is greater than 1, it is taken as 1:

[0111]

[0112]

[0113]

[0114] In formulas (12), (13) and (14), the reference value of the index is the measured value of the reference point in the river and lake survey points, or the calculated value of the river and lake reference state. Dominance = density of a single algae / total algae density, among which the algae with dominance > 2% are the dominant species.

[0115] (3.1.2) The phytoplankton integrity index is calculated using formula (15):

[0116]

[0117] (3.1.3) Evaluation criteria are as shown in Table 3.1-1

[0118] Table 3.1-1 Evaluation criteria and grading table of algae integrity index

[0119]

[0120] In a certain monitored area, if the reservoir type belongs to a non-accessible river type drinking water source, according to the river basin to which it belongs, the reference values ​​in the flood season are: Py1=55, Py2=4104963.89, Py3=0.37; the reference values ​​in the dry season are: Py1=43, Py2=2831236.83, Py3=0.42.

[0121] If the drinking water source is evaluated as a deep-water lake or reservoir, the reference values ​​are shown in Table 3.1-2:

[0122] Table 3.1-2 Reference status values ​​of algae integrity index for drinking water sources in Shenzhen

[0123]

[0124] In addition, based on the results of the aquatic biological integrity survey in this embodiment and historical surveys, reference values ​​of Py1, Py2 and Py3 for the flood season and dry season of drinking water sources of types A and B can be formulated.

[0125] (3.2) Benthic Invertebrate Integrity Index (B-IBI)

[0126] The IBI index is selected to comprehensively reflect the stability of the species composition, diversity and function of a large benthic animal community in a region. Three parameters, namely the total number of taxa, the Biological Monitoring Working Party (BMWP) index and the BP index, are selected for calculation. The total number of taxa refers to the total number of species identified at each monitoring sample point, which can reflect the abundance of the community. The BMWP index is based on the presence or absence of each species in the family-level taxonomic unit, taking into account the sensitivity value of the species that appear, and the sensitivity value of all the species that appear, and the sum of the sensitivity values ​​of all the species that appear represent the environmental situation. The BP index is the dominance index of dominant species (the dominance of a certain benthic animal = the density of a certain benthic animal / the total density of benthic animals, and the benthic organisms with a dominance greater than 2% are dominant species). The values ​​of these three parameters are obtained through the collection, identification and quantitative analysis of aquatic organisms.

[0127] (3.2.1) Calculation of single index:

[0128] The calculation method of the single index of macrobenthic invertebrate integrity is as follows: Formula (16), (17), (18). If the result is greater than 1, it is taken as 1:

[0129]

[0130]

[0131]

[0132] In formulas (16), (17), and (18), the reference values ​​of the indicators are the measured values ​​at the reference points in the river and lake survey, or the calculated values ​​of the river and lake reference conditions.

[0133] (3.2.2) The benthic invertebrate integrity index is calculated using formula (19):

[0134]

[0135] (3.2.3) Evaluation criteria are shown in Table 3.2-1

[0136] Table 3.2-1 Evaluation criteria and grading table of benthic animal integrity index

[0137]

[0138] For the setting of reference values, see Table 3.2-2:

[0139] Table 3.2-2 Reference value setting of B-IBI for drinking water sources in the monitored area

[0140]

[0141]

[0142] (3.3) Fish Ownership Index (FOEI)

[0143] The fish abundance index (FOEI) is used to assess the fish integrity and is calculated using formula (20):

[0144]

[0145] The number of current fish species is obtained through on-site investigation, monitoring and questioning (excluding exotic fish species), and the historical fish species are determined by investigating historical fish fishing data and consulting experts. If the historical fish data of the drinking water source in the monitored area is relatively scarce and it is impossible to trace back to the 1980s or earlier historical data, it is recommended to refer to early books and documents, or send a letter to the relevant department to request relevant information, or consult experts in this field, or refer to the fish tracing information in the historical species of lake sediments based on environmental DNA technology.

[0146] The evaluation criteria are shown in Table 3.3-1:

[0147] Table 3.3-1 Evaluation criteria and grading table of fish stock index

[0148]

[0149] (3.4) Rare species abundance, alien species invasion rate and pollution-tolerant species dominance

[0150] Changes in rare, local, alien and pollution-tolerant aquatic organisms: Based on aquatic organism survey data, the number and biomass of rare, local, alien and pollution-tolerant species are determined, and the richness of rare species, the invasiveness of alien species and the dominance of pollution-tolerant species are calculated. This can be evaluated by scoring by experts in this field.

[0151] After the evaluation of each sub-item indicator in the above three assessment layers is completed, the summary is conducted to conduct a comprehensive water ecological evaluation of the drinking water source in the monitored area, classify the levels, complete the corresponding indicator filling, and form a flood season and dry season report in stages:

[0152] Corresponding monitoring and evaluation reports are generated for different drinking water sources to be monitored in different water periods. The average score of each indicator in each evaluation layer is taken, and the total score is calculated through the weighted average of the evaluation layers. Taking a certain area as an example, the weights of the three evaluation layers are set according to the water ecological conditions of the area: water quality assessment layer weight 0.3, habitat assessment layer weight 0.3, biological assessment layer weight 0.4, and the final score is calculated, and the corresponding grade is evaluated according to Table I.

[0153] Table Ⅰ Final evaluation score standard of water ecological health in a certain area

[0154] Rating excellent good middle Difference inferior Points 25,24,23,22,21 20,19,18,17,16 15,14,13,12,11 10,9,8,7,6 5,4,3,2,1,0

[0155] The following application examples are to use the drinking water source water ecological health assessment system and method of the present invention to assess different drinking water sources in a certain area:

[0156] Among them, the drinking water sources to be monitored are: Reservoir 1, Reservoir 2, Reservoir 3 and Reservoir 4. Reservoir 1, Reservoir 2 and Reservoir 3 are Class A drinking water sources, which mainly use external water transfer, are surrounded by built-up areas, and have relatively average water quality. Reservoir 4 is a Class B drinking water source, which mainly uses self-produced water, is located in a non-built-up area, and has relatively good water quality.

[0157] The water ecology assessment during the flood season selects the monitoring and investigation results from June to August of a certain year, and the water ecology assessment during the dry season selects the monitoring and investigation results from November and December of the same year as the flood season and January of the following year.

[0158] (4.1) Water quality index assessment results

[0159] 4.1.1 Water quality compliance rate (%), as shown in Table 4-1:

[0160] Table 4-1 Evaluation results of water quality compliance rates of four major drinking water sources in a certain region

[0161]

[0162] 4.1.2 Proportion of surface water of good quality (reaching or exceeding Class III) (%)

[0163] In the evaluation system of the present invention, all unretained inflow tributaries are regarded as first-level tributaries to calculate the excellent surface water ratio. Only Reservoir 1 meets the conditions. Its inflow tributaries are River 1 and River 2. The excellent surface water ratio of Reservoir 1 is monitored, and Table 4-2 is obtained:

[0164] Table 4-2 Proportion of excellent (reaching or exceeding Class III) surface water in Reservoir 1 (%)

[0165] Water period Flood season Dry season Water quality compliance rate 84.33％ 50.00％ Rating good inferior Points 17 5

[0166] 4.1.3 Proportion of surface water of Class V (%)

[0167] Only Reservoir 1 meets the requirement. The reason is the same as 4.1.2 Excellent surface water ratio (%). Table 4.3 shows the monitoring results of Reservoir 1:

[0168] Table 4-3 Proportion of surface water in Class V (%)

[0169] Water period Flood season Dry season Water quality compliance rate 0％ 0％ Rating excellent excellent Points 25 25

[0170] 4.1.4 Comprehensive Nutrition Status Index (TLI), as shown in Table 4-4

[0171] Table 4-4 Evaluation results of comprehensive nutritional status index (TLI) of four main drinking water sources in a certain region

[0172]

[0173] (4.2) Habitat indicator assessment results

[0174] 4.2.1 Lake and reservoir entrance patency rate (%)

[0175] Since the habitat of lakes and reservoirs changes little, the habitat survey is only conducted once a year. The habitat index assessment is not divided into water periods. The specific habitat monitoring is shown in Table 4-5:

[0176] Table 4-5 Evaluation results of the accessibility of lake and reservoir gates at four major drinking water sources in a certain region

[0177]

[0178] 4.2.2 Vegetation coverage of lakeside ecological buffer zone (%)

[0179] The specific monitoring and evaluation results are shown in Table 4-6:

[0180] Table 4-6 Evaluation results of vegetation coverage in the lakeside ecological buffer zones of four major drinking water sources in a certain region

[0181]

[0182]

[0183] 4.2.3 Habitat complexity of lakeside ecological buffer zone (%)

[0184] This item is not monitored.

[0185] 4.2.4 Wetland Degradation Index

[0186] The specific monitoring and evaluation results are shown in Table 4-7:

[0187] Table 4-7 Wetland degradation index assessment results of four major drinking water sources in a certain region

[0188] Monitoring points Reservoir 1 Reservoir 2 Reservoir 3 Reservoir 4 Wetland Degradation Index 0.3 -96.99 -0.56 8.7 Rating good excellent excellent middle Points 20 25 25 12

[0189] 4.3 Biological indicator evaluation results

[0190] 4.3.1 Algal integrity index (P-IBI)

[0191] The specific scoring method is shown in Table 4-8, and the specific monitoring and evaluation results are shown in Table 4-9:

[0192] Table 4-8 Scoring method for the algae integrity index (P-IBI) of four main drinking water sources in a certain region

[0193]

[0194] Table 4-9 Evaluation results of the algae integrity index (P-IBI) of four major drinking water sources in a certain region

[0195]

[0196] Analysis Table 4-8: The P-IBI of Reservoir 1 and Reservoir 2 decreased during the dry season, and the main reason was the low algae density. For natural lakes and reservoirs, the algae density should be maintained at a certain level to assume its role as a primary producer and maintain the health of the water ecology. However, whether this is necessary for artificial lakes and reservoirs remains to be discussed. The evaluation method of phytoplankton indicators can be appropriately adjusted in subsequent investigations and studies. The P-IBI of Reservoir 3 during the wet and dry seasons was 1.18 and 1.28, respectively, with scores of 4 and 3, and the evaluation grades were both poor. The main reason for this result was that the algae density in Reservoir 3 was too high, the dominance of the top three dominant species was too large, and the diversity was low. The P-IBI of Reservoir 4 during the wet season was 0.94, with a score of 0, and the evaluation grade was poor, mainly because the algae density was too low.

[0197] 4.3.2 Fish Ownership Index (FOEI)

[0198] In the fish survey of four drinking water sources in a certain area from December of the previous year to February of the next year of this monitoring year, a total of 27 local fish species were found, including crucian carp, anchovy, thick-lipped catfish, silver carp, The spotted tongue goby, catfish, dace, big-eyed red carp, Ziling goby, bream, carp, yellowtail carp, snake goby, seven-thread anchovy, golden tongue goby, Hainan red carp, yellow eel, crucian carp, black snakehead, brown snakehead, Xingkai spiny carp, bearded catfish, tongue goby, bighead carp, striped spiny carp and black carp are basically economic fish.

[0199] During this monitoring, the number of local fish species captured in reservoirs 1, 2, 3 and 4 during the flood season was 6, 3, 1 and 3, and the number of local fish species captured during the dry season was 9, 5, 3 and 1. The evaluation grades were all poor, indicating that the number of local fish species in the four drinking water sources in the area is too small and the diversity is poor. It is speculated that there are still some species of local fish in the drinking water sources that were not captured in this survey. The fish survey method can be improved in future work, such as introducing advanced technical means such as environmental DNA to improve fish surveys.

[0200] The specific monitoring and evaluation results are shown in Table 4-10:

[0201] Table 4-10 Evaluation results of fish abundance index (FOEI) of four main drinking water sources in a certain region

[0202]

[0203] 4.3.3 Rare species, local species, exotic species, and pollution-tolerant species

[0204] No protected animals stipulated by Chinese law were found in the four drinking water sources. The number of local fish species was low and the phenomenon of alien invasion was very serious. The dominant species of phytoplankton and zooplankton were also mainly widespread species and pollution-resistant species, which were at a medium level. The specific evaluation results are shown in Table 4-11:

[0205] Table 4-11 Evaluation results of rare species, local species, exotic species and pollution-tolerant species in four major drinking water sources in a certain region

[0206]

[0207]

[0208] According to the results of Table 4-1 to Table 4-11, the average of the sub-item indicators of the same reservoir and the same assessment layer during the flood season or dry season is calculated to obtain the score of the reservoir in the assessment layer. Then, the weighted average is calculated according to the weights of the three assessment layers of the reservoir to obtain the water ecological assessment value of the reservoir during the flood season. Finally, the results are summarized in Table 5:

[0209] Table 5 Final evaluation results of water ecology of four main drinking water sources in a certain region (system and method of the present invention)

[0210]

[0211] The four main drinking water sources in the region were evaluated using existing survey and evaluation methods. The results are shown in Table 6:

[0212] Table 6 Water ecological assessment results of four major drinking water sources in a certain region (existing survey and evaluation methods)

[0213]

[0214]

[0215] Comparing Table 5 and Table 6, the evaluation results obtained by the existing investigation and evaluation methods are: excellent 2 and good 6; the evaluation results of the evaluation system and method of the present invention are: good 7 and 1. This phenomenon is mainly due to the fact that the main drinking water sources in the monitoring area in this embodiment generally have poor aquatic biodiversity, a certain risk of algal blooms, and serious invasion of alien fish, resulting in generally low scores for biological indicators. In the evaluation system of the present invention, the biological indicators in this area account for a large proportion of the weight, and the evaluation results obtained are also lower.

[0216] In summary, the water ecological health assessment system and method for drinking water sources of the present invention are more suitable for water ecological health assessment in areas with high algal toxin content, lack of early fish data, and all tributaries entering the drinking water source are secondary tributaries.

Claims

1. A water ecological health assessment method based on the water ecological health assessment system of drinking water sources, It is characterized in that The water ecological health assessment method comprises the following steps: S1. The water ecological health assessment system based on the water ecological health assessment method includes: a water quality assessment layer, a habitat assessment layer and a biological assessment layer; the weights of the water quality assessment layer, the habitat assessment layer and the biological assessment layer are X1, X2 and X3 respectively, and X1, X2 and X3 are determined according to the water ecological conditions of the area to be monitored, and X1+X2+X3=1; The water quality assessment layer includes the following water quality index sub-items: water quality compliance rate, excellent surface water ratio, surface water ratio worse than Class V, and comprehensive nutrient status index; The habitat assessment layer includes the following habitat index sub-items: lake and reservoir entrance accessibility, lakeside ecological buffer zone vegetation coverage, wetland degradation index and habitat complexity; The biological assessment layer includes the following biological indicator sub-items: phytoplankton integrity index, benthic invertebrate integrity index, fish stock index, and changes in rare species, native species, alien species, and pollution-tolerant aquatic organisms; The screening of indicator sub-items for water quality indicator sub-items, habitat indicator sub-items and biological indicator sub-items is determined based on the water ecological environment characteristics and ecological service functions of the area to be monitored; S2. Constructing a water ecological health assessment system for the area to be monitored: According to the water ecological health assessment system described in S1, determine the values ​​of the weights X1, X2, and X3 of the water quality assessment layer, habitat assessment layer, and biological assessment layer for the water ecological health assessment of the area to be monitored; and select water quality index sub-items, habitat index sub-items, and biological index sub-items used to characterize the water ecological environment status of the area to be monitored from the water quality assessment layer, habitat assessment layer, and biological assessment layer respectively; S3, monitoring of water ecology index sub-items in the area to be monitored: according to the water quality index sub-items, habitat index sub-items and biological index sub-items selected in step S2, the water ecology of the area to be monitored is monitored and the monitoring results of each index sub-item are calculated; S4. Water ecological health assessment of the monitored area: determine the scores of each indicator sub-item of the water ecology of the monitored area according to the monitoring results of the water quality indicator sub-items, habitat indicator sub-items and biological indicator sub-items obtained in step S3, then calculate the average scores of the indicator sub-items in the same assessment layer to obtain the scores of the three assessment layers, calculate the weighted average of the scores of the obtained assessment layers according to the weights of step S1, and obtain the final score of the water ecology of the monitored area, and obtain the water ecological health assessment level of the monitored area according to the final score.

2. The water ecological health assessment method based on the water ecological health assessment system of drinking water source according to claim 1 is characterized in that: The weights X1, X2 and X3 of the water quality assessment layer, habitat assessment layer and biological assessment layer are 0.3, 0.3 and 0.4 respectively.

3. The water ecological health assessment method based on the water ecological health assessment system of drinking water source according to claim 1 is characterized in that: The water quality compliance rate is calculated by formula (1): The water quality monitoring indicators of the water quality compliance rate include: pH, dissolved oxygen, ammonia nitrogen, total nitrogen, total phosphorus, permanganate index, chemical oxygen demand, five-day biochemical oxygen demand and algae toxins MC-LR and CYN; The good surface water ratio is calculated by formula (2): The surface water quality of Class V is calculated by formula (3): The water quality monitoring indicators for the proportion of good surface water and the proportion of surface water inferior to Class V include: pH, dissolved oxygen, ammonia nitrogen, total nitrogen, total phosphorus, permanganate index, chemical oxygen demand and five-day biochemical oxygen demand; The calculation method of the comprehensive nutritional status index TLI is as follows: Taking the chlorophyll a status index TLI (Chla) as the benchmark, the transparency (SD) parameter is used as the nutritional status index indicator, and weighted synthesis is performed with TLI. The comprehensive weighted index model is formula (4): In formula (4), TLI(∑) is the comprehensive weighted nutritional status index; TLI(j) is the nutritional status index of the jth parameter; W j The weight of the nutritional status index of the jth parameter, W j Calculate according to formula (5): In formula (5): r ij is the correlation coefficient between the jth parameter and the reference parameter chla, r of transparency (SD) ij The value is 0.83; m is the number of evaluation parameters; TLI(SD) is calculated by formula (6): TLI(SD)=10×(5.118-1.94lnSD) Formula (6); In order to distinguish the water ecological function characteristics of different survey objects, the comprehensive nutrient status index needs to be normalized and calculated. The calculation formula is formula (7): TLI 最大值 TLI is the maximum value of the comprehensive nutritional index among the survey points in the monitoring area. 参考 TLI is the comprehensive nutritional index value of the reference point or reference state of the lake or reservoir. i is the comprehensive nutritional index value of survey point i.

4. The water ecological health assessment method based on the water ecological health assessment system of drinking water source according to claim 1 is characterized in that: The lake and reservoir entrance patency rate is calculated by formula (8): The vegetation coverage of the lakeside ecological buffer zone is calculated by formula (9): The wetland degradation index is calculated by formula (10): The habitat complexity is calculated by formula (11): The habitat complexity mentioned refers to the habitat within the lake-reservoir buffer zone, and the lake-reservoir buffer zone is within 33m of the lake-reservoir shoreline.

5. The water ecological health assessment method based on the water ecological health assessment system of drinking water source according to claim 1 is characterized in that: The phytoplankton integrity index is calculated by biomass density, total number of taxa and Berger-Parker index, and the calculation method is: (1-1) Calculation method of single phytoplankton integrity index: In formulas (12), (13), and (14), the reference value is the measured value of the reference point in the river and lake survey points or the calculated value of the river and lake reference state, dominance = single algae density / total algae density, and algae with dominance > 2% are dominant species; When the calculation results of formulas (12), (13), and (14) are negative, the calculation results are taken as 0. When the calculation results are greater than 1, the calculation results are taken as 1. (1-2) The phytoplankton integrity index is calculated by formula (15): The benthic invertebrate integrity index is calculated by the total number of taxa, the BMWP index and the BP index: (2-1) Calculation method of single benthic invertebrate integrity index: In formulas (16), (17), and (18), the reference value of the index is the measured value of the reference point in the river and lake survey points, or the calculated value of the river and lake reference state; (2-2) The benthic invertebrate integrity index is calculated using formula (19). When the calculated result is greater than 1, the calculated value is taken as 1: The fish stock index is calculated by formula (20): The changes in the rare, local, alien and pollution-tolerant aquatic organisms are determined based on aquatic organism survey data, and the number and biomass of rare, local, alien and pollution-tolerant species are determined, and the richness of rare species, the invasiveness of alien species and the dominance of pollution-tolerant species are calculated.

6. The water ecological health assessment method based on the water ecological health assessment system of drinking water source according to claim 1 is characterized in that: The monitored area is divided into Class A drinking water source and Class B drinking water source according to water quality. Class A drinking water source is a drinking water source that mainly uses external water and is surrounded by built-up areas; Class B drinking water source is a drinking water source that mainly uses self-produced water and is located in non-built-up areas.

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