Construction method of water purification system in ecological wetland flood storage area based on wetland unit

Abstract

The method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit disclosed in the present invention includes: (1) functionally zoning and arranging a wetland area; (2) arranging plants for each functional zone; (3) demarcating each functional zone into wetland units and arranging the scale and location of the inlet and outlet water buildings of the wetland; (4) implementing an ecological restoration project in the ecological restoration area of ​​the wetland; (5) evaluating whether the water purification effect of the wetland meets the preset requirements based on the inlet and outlet water quality of the wetland after the implementation of the ecological restoration project; (6) evaluating whether the water purification effect of each wetland unit meets the preset requirements based on the inlet and outlet water quality of each wetland unit. The present application constructs a water purification system that can give full play to the water purification effect while minimizing the amount of engineering work, and is particularly suitable for the construction of ecological wetland flood storage areas with large areas, complex terrains and diverse land use types.

Description

Technical Field

[0001] The present application belongs to the technical field of ecological wetland construction, and in particular to a method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit. Background Art

[0002] Ecological wetland flood storage areas often need to take into account both ecological functions and flood storage functions. When encountering super-standard floods, the gates are opened to allow floods to enter, and floods are stored to reduce the flood peak; when there is no flood, the main ecological functions are ecological restoration, water purification, etc. At present, the construction of water purification systems based on ecological wetlands is mostly carried out in a large-scale excavation manner, which has a large amount of engineering and causes a huge waste of manpower and material resources. Especially for ecological wetland flood storage areas with large areas, diverse land use types, and flood storage functions, this large-scale excavation method has a huge workload and high costs. For ecological wetland flood storage areas with large areas, diverse land use types, and flood storage functions, how to construct a water purification system that fully exerts the water purification effect while minimizing the amount of engineering is the current technical difficulty. Summary of the invention

[0003] The purpose of this application is to provide a method for constructing a water purification system for an ecological wetland flood storage area based on wetland units. This application can construct a water purification system that fully exerts the water purification effect while minimizing the amount of engineering work. It is particularly suitable for the transformation of ecological wetland flood storage areas with large areas, diverse land use types and flood storage functions.

[0004] To achieve the above-mentioned purpose, the present application provides a method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit, comprising:

[0005] (1) The wetland area is divided into functional zones, including water distribution main canals, multi-field wetland areas, swamp wetland areas, and forest and grassland wetland areas;

[0006] (2) Analyze the soil nutrients in each functional zone, with the goal of reducing the release of endogenous pollution in the functional zone, and configure plants in each functional zone according to the soil nutrients;

[0007] (3) Delineate wetland units in the field wetland area, marsh wetland area, and forest and grassland wetland area, and determine the water allocation for each wetland unit. On the premise of meeting the water inlet and outlet needs of each wetland unit, plan the scale and location of the wetland's water inlet and outlet structures;

[0008] (4) Implementing ecological restoration projects in the wetland area according to steps (1) to (3); the implementation of ecological restoration projects at least includes the construction of functional zoning and wetland units, the construction of vegetation configuration projects, and the construction of water inlet and outlet buildings;

[0009] (5) Based on the inlet and outlet water quality of the wetland after the implementation of the ecological restoration project, evaluate whether the water purification effect of the wetland area meets the preset requirements. If it does, the process ends; if it does not, proceed to step (6);

[0010] (6) Based on the inlet and outlet water quality of each wetland unit, evaluate whether the water purification effect of each wetland unit meets the preset requirements; optimize the ecological restoration project for wetland units that do not meet the preset requirements until the water purification effect of the wetland unit meets the preset requirements.

[0011] Furthermore, the wetland units of the multi-field wetland area, the marsh wetland area and the forest and grassland wetland area are delineated, including:

[0012] 3.1 The existing ditches in the ecological wetland flood storage area are arranged into inlet branches and outlet branches, and the inlet branches and outlet branches on the same side of the water distribution main canal are arranged alternately along the direction of the water distribution main canal;

[0013] 3.2 Use the outlet canals to divide each functional area into sub-areas;

[0014] 3.3 The sub-region is divided into two patches using the inlet canals contained in the sub-region, and each patch is further divided into several small patches along the inlet canals, namely wetland units;

[0015] The layout of the scale and location of the wetland water inlet and outlet structures includes:

[0016] Arrange inlet culverts and outlet culverts at the inlet of the inlet branch canal and the outlet of the outlet branch canal respectively, and select inlet culverts and outlet culverts of appropriate scale according to the amount of purifiable water in the sub-district where the inlet branch canal and the outlet branch canal are located;

[0017] Arrange waterfall weirs in sections on the water inlet branch channel;

[0018] Furthermore, the amount of water that can be purified in a sub-district is the sum of the water allocations of all wetland units within the sub-district;

[0019] The water distribution of the wetland unit adopts the preset target water distribution of the wetland unit or is predicted according to the maximum hydraulic load per unit area of ​​the wetland unit;

[0020] The maximum hydraulic load per unit area of ​​the wetland unit is determined based on the wetland layout and the plant configuration obtained in step (2) in combination with engineering experience.

[0021] Furthermore, the construction of functional zones and their wetland units includes micro-topography treatment of the functional zones and their wetland units, and the construction of ridges to separate the wetland units, so that the wetland units are independent of each other;

[0022] The functional zones and their wetland units are processed with micro-topography, including:

[0023] Micro-modification of the terrain of each functional zone is carried out so that the functional sub-zones on the same side of the water distribution main channel meet the following requirements: the ground elevation of each sub-zone decreases along the water flow direction of the water distribution main channel;

[0024] The terrain of each wetland unit in the sub-division is slightly modified so that the wetland units located on the same side of the same inlet branch canal meet the following requirements: the ground elevation of each wetland unit decreases along the water flow direction of the inlet branch canal.

[0025] Further, the construction of water inlet and outlet structures includes:

[0026] An inlet culvert is constructed at the water inlet of each inlet branch canal, and an outlet culvert is constructed at the water outlet of each outlet branch canal; a waterfall weir is constructed in sections on each inlet branch canal; an inlet culvert connecting the inlet branch canal and an outlet culvert connecting the outlet branch canal are installed in each wetland unit.

[0027] In the further construction of water inlet and outlet buildings, it also includes:

[0028] According to the purifiable water volume of the sub-district, build water inlet culverts at the water inlet of the water inlet branch channel contained in the sub-district, so that the water volume entering the sub-district is not greater than the purifiable water volume;

[0029] According to the water distribution of each wetland unit, a water inlet culvert connected to the wetland unit is constructed so that the amount of water entering the wetland unit is not greater than the water distribution of the wetland unit.

[0030] Furthermore, the construction of water inlet and outlet structures also includes:

[0031] A main water inlet culvert is built upstream of the external water system and connected to the water distribution main canal. An outlet pumping station is built downstream of the external water system and connected to the outlet main canal.

[0032] Furthermore, when there are ponds in the existing ecological wetland flood storage area, the construction of the water inlet and outlet structures also includes: transforming the ponds into purification ponds, and connecting the purification ponds in series with the nearest water inlet channel or water outlet channel.

[0033] The ecological wetland flood storage area water purification system based on the wetland unit constructed by the above construction method includes a water inlet unit, a water outlet unit and a water purification area;

[0034] The water inlet unit includes a water distribution main channel and a plurality of water inlet branch channels connected to the water distribution main channel; the water outlet unit includes a water outlet main channel and a plurality of water outlet branch channels connected to the water outlet main channel; and the water inlet branch channels and the water outlet branch channels on the same side of the water distribution main channel are arranged alternately along the direction of the water distribution main channel;

[0035] The water purification area includes a plurality of functional zones, each of which is divided into functional sub-zones by the outlet branch canals it contains, each functional sub-zone is divided into two patches by the inlet branch canals it contains, and each patch is divided into a number of independent wetland units distributed along the inlet branch canals by the ridges; each wetland unit is connected to the inlet branch canals and the outlet branch canals of the patch where it is located through the inlet culvert and the outlet culvert respectively;

[0036] The ground elevation of each functional sub-area located on the same side of the water distribution main canal decreases along the water flow direction of the water distribution main canal; the ground elevation of the wetland unit located on the same side of the same water inlet branch canal decreases along the water flow direction of the water inlet branch canal.

[0037] Furthermore, the functional zoning includes at least two of the following: forest and grassland wetland areas, paddy field wetland areas, and swamp wetland areas.

[0038] Compared with the prior art, this application has the following characteristics and beneficial effects:

[0039] 1. This application constructs a water purification system that can fully exert the water purification effect while minimizing the amount of engineering work. It is particularly suitable for the transformation of ecological wetland flood storage areas with large areas, complex terrain and diverse land use types.

[0040] 2. Furthermore, this application is closely integrated with the existing topography of the flood storage area, relying on the existing farmland texture and pond water system in the flood storage area to layout and construct an ecological wetland flood storage area water purification system based on wetland units, using the least amount of engineering to ensure that waste water can flow through all areas of the flood storage area in space, and to achieve precise water distribution in each wetland unit, so as to maximize the water purification effect of the flood storage area. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the process for constructing the method for this application;

[0042] Figure 2~3 All of them are schematic diagrams of the current status of the ecological wetland flood storage area in the embodiments;

[0043] Figure 4 It is a schematic diagram of the zoning layout of the ecological wetland flood storage area in the embodiment;

[0044] Figure 5 Schematic diagram of wetland unit division of ecological wetland flood storage area in the embodiment;

[0045] Figure 6 for Figure 5 Schematic diagram of wetland units contained in the medium functional sub-district DT-01.

[0046] In the figure, there is a river 1, a pond 2, a ditch 3, an inlet branch canal 4, an outlet branch canal 5, a water distribution main canal 6, an outlet main canal 7, an inlet culvert 8, and an outlet culvert 9. DETAILED DESCRIPTION

[0047] The specific implementation of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the specific implementation described does not limit the present application. Based on the specific implementation in the present application, all other specific implementations obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0048] See also Figure 1 , shown is a flow chart of the construction method of the ecological wetland flood storage area water purification system of this application, and the following will be combined with Figure 1 , the specific implementation process of this application is described in detail, and the specific steps are as follows:

[0049] (1) The wetland area is divided into functional zones, including water distribution main canals, multi-field wetland areas, swamp wetland areas, and forest and grassland wetland areas;

[0050] In order to reduce the amount of engineering work, the current status of the ecological wetland flood storage area should be comprehensively considered when carrying out the functional zoning layout, and the principle of minimum engineering work should be followed. At the same time, the relatively low-lying areas should be demarcated as multi-field wetland areas and swamp wetland areas, and the relatively high-lying areas should be demarcated as forest and grass wetland areas. The current status of the above-mentioned ecological wetland flood storage area at least includes topography, land use type, river system distribution, planted vegetation, and layout of water inlet and outlet buildings.

[0051] Specifically, first determine the current land use types of the ecological wetland flood storage area based on the land survey data of the land department, such as cultivated land, forest land, grassland, water area, etc. Then, layout the existing cultivated land areas in the ecological wetland flood storage area into multi-field wetland areas and swamp wetland areas, specifically layout the multi-field wetland areas and swamp wetland areas according to the depth of the water level in the existing cultivated land areas, and layout the existing cultivated land areas with shallower water levels into swamp wetland areas; layout the existing forest land and grassland areas into forest and grassland wetland areas, and layout the existing rivers into water distribution main channels.

[0052] See also Figure 2~3 , which is a schematic diagram of the current status of the ecological wetland flood storage area. The current ecological wetland flood storage area has a river 1, and there are also several ponds 2 and ditches 3 (not all ponds and ditches are marked in the figure). The blue and red broken lines in the figure represent ditches. In this embodiment, the existing cultivated land area is located on the left side of the river 1, and the forest and grassland areas are located on the right side of the river 1. The numbers in the figure represent the average ground elevation of the corresponding area, and different elevation areas are indicated by green dotted lines. For details, see Figure 3 . See Figure 4, shown is a schematic diagram of the zoning layout of the ecological wetland flood storage area. According to the water level depth of the existing cultivated land area, the existing cultivated land area is arranged into multi-field wetland areas and swamp wetland areas. Among them, DT-01 and DT-02 are multi-field wetland areas, and ZZ-01 and ZZ-02 are swamp wetland areas.

[0053] (2) Analyze the soil nutrients in each functional zone, with the goal of reducing the release of endogenous pollution in the functional zone, and configure plants in each functional zone according to the soil nutrients;

[0054] By analyzing soil nutrients, we can determine whether there is a possibility of soil nutrients entering the water body when it is transformed into a wetland ecosystem, as well as the difficulty of soil nutrients entering the water body. We can also screen and configure suitable plants for each functional zone to effectively reduce the release of endogenous pollution in each functional zone.

[0055] Specifically, soil nutrients can be analyzed by sampling and testing the composition of soil in each functional zone, or by theoretical analysis based on the original land use pattern of the functional zone. Land use patterns include farmland, forest and grassland, and swampland.

[0056] When configuring plants, the pollution resistance and decontamination capabilities of various types of plants should be analyzed first, and the adaptability of various types of plants to different environments should be considered, so as to select wetland plants for the purpose of exerting the purification effect of plants. Furthermore, when configuring plants, the economic value, landscape effect and ecological safety of plants should also be considered at the same time.

[0057] Pollution tolerance and decontamination ability are important principles for selecting wetland plants. The decontamination ability of plants is closely related to the growth status of the plants and the degree of development of their root systems. Large species such as Typha longibracteata and Water Candle have thick root systems and many developed adventitious roots, making them better water purification plants.

[0058] (3) Delineate wetland units including multi-field wetland areas, swamp wetland areas, and forest and grassland wetland areas, and determine the water allocation for each wetland unit. Arrange the scale and location of wetland water inlet and outlet structures based on the water allocation and layout of the wetland units.

[0059] In order to improve the water treatment efficiency and effect of the water purification system in the ecological wetland flood storage area, the multi-field wetland area, swamp wetland area and forest and grassland wetland area will be further delineated as wetland units, including:

[0060] 3.1 The existing ditches in the ecological wetland flood storage area are arranged into inlet branch channels and outlet branch channels, and the inlet branch channels and the outlet branch channels on the same side of the water distribution main channel are arranged alternately along the direction of the water distribution main channel; in this embodiment, inlet branch channels and outlet branch channels are arranged on both sides of the water distribution main channel, and on each side of the water distribution main channel, there are: inlet branch channels and outlet branch channels are arranged alternately along the direction of the water distribution main channel.

[0061] When the existing ditch is laid out as an inlet branch canal and an outlet branch canal, the disconnected ditch can be connected by excavation or laying culverts to obtain an inlet branch canal or an outlet branch canal.

[0062] See also Figures 4 and 5 , shows the distribution of the inlet branch channel and the outlet branch channel in the embodiment, in which the red broken line represents the inlet branch channel 4, whose water inlet is connected to the water distribution main channel 6; the blue broken line represents the outlet branch channel 5, whose water outlet is connected to the outlet main channel 7. In this embodiment, the distance between adjacent inlet branch channels and outlet branch channels is 300m to 500m.

[0063] 3.2 Use the outlet branch canals to divide each functional zone into sub-zones. Specifically, the area between two adjacent outlet branch canals in each functional zone is divided into a sub-zone. Then, each functional sub-zone has one inlet branch canal and two outlet branch canals.

[0064] See also Figure 4 The Duotian wetland area is divided into two sub-divisions, DT-01 and DT-02, by the outlet branch canals; the swamp wetland area is divided into two sub-divisions, ZZ-01 and ZZ-01, by the outlet branch canals; the forest and grassland wetland area is divided into five sub-divisions, LC-01, LC-02, LC-03, LC-04, and LC-05, by the outlet branch canals.

[0065] 3.3 The sub-district is divided into two patches using the inlet branch canals contained in the sub-district, and each patch is further divided into several small patches along the inlet branch canals, namely wetland units; the size of the wetland unit in this application is: 50~60m wide and 150m~350m long; the wetland unit is generally set as a multi-field wetland of level 2-5 on the basis of making full use of the existing terrain;

[0066] Each patch has an inlet and outlet canal to achieve water inflow and outflow in the patch area. The number of wetland units divided by each patch in the same sub-area can be equal or unequal. The division of wetland units can be shown in Figures 5 and 6 The green solid line in the figure represents the dividing line of the wetland unit. Taking sub-area DT-01 as an example, it is divided into six wetland units: A1, A2, A3, A4, A5, and A6.

[0067] After the wetland units are delineated, the water allocation of each wetland unit is calculated. Specifically, the water allocation of the wetland unit adopts the preset target water allocation of the wetland unit, or is predicted based on the maximum hydraulic load per unit area of ​​the wetland unit. Prediction based on the maximum hydraulic load per unit area of ​​the wetland unit includes: determining the maximum hydraulic load per unit area of ​​the wetland unit based on the wetland layout and the plant configuration obtained in step (2), combined with engineering experience, and the product of the maximum hydraulic load per unit area and the area of ​​the wetland unit is the water allocation of the wetland unit. The sum of the water allocations of all wetland units in a sub-division is the amount of water that can be purified in the sub-division.

[0068] Specifically, the scale and location of the wetland's water inlet and outlet structures are planned, including:

[0069] An inlet culvert is arranged at the water inlet of the inlet branch canal, and an outlet culvert is arranged at the water outlet of the outlet branch canal. The inlet culvert and the outlet culvert are used to control the water flow and water volume in and out. The inlet culvert and the outlet culvert of appropriate size are selected according to the amount of purified water in the sub-district where the inlet branch canal and the outlet branch canal are located;

[0070] The purpose of arranging drop weirs in sections on the water inlet branch channel is to form a drop so that the water flows naturally in the water inlet branch channel; in this embodiment, the elevation of the top of the drop weir is 0.3m~0.5m lower than the ground elevation, and the distance between adjacent drop weirs on the same water inlet branch channel is 300m~500m;

[0071] On the water inlet branch channel, a number of water inlet culverts corresponding to each wetland unit are arranged to introduce the water flow in the water inlet branch channel into the corresponding wetland unit to ensure uniform water distribution to the wetland unit;

[0072] A number of outlet culverts corresponding to the wetland units are arranged on the outlet branch channel to lead the water flow purified by the wetland unit to the outlet branch channel.

[0073] See also Figures 5 and 6 The water in the water distribution main channel 6 flows through the water inlet culvert 8 into each water inlet branch channel 4, and then enters each independent wetland unit from the water inlet branch channel 4 through the water inlet culvert pipe. After being purified by the wetland unit, the water flows out to the water outlet branch channel 5 through the water outlet culvert pipe, and then enters the water outlet main channel 7 or the water distribution main channel 6 through the water outlet culvert 9 for discharge. It should be noted that in this application, the water inlet of each water inlet branch channel is equipped with a water inlet culvert, and the water outlet of each water outlet branch channel is equipped with a water outlet culvert. Figure 5 Not all inlet and outlet culverts are marked.

[0074] (4) According to steps (1) to (3), implement ecological restoration projects in the ecological wetland flood storage area; the implementation of ecological restoration projects at least includes the construction of functional zoning and its wetland units, the construction of vegetation configuration projects, and the construction of water inlet and outlet buildings.

[0075] In this step, the construction of functional zones and their wetland units includes micro-topography processing of the functional zones and their wetland units, and the construction of ridges to separate the wetland units.

[0076] Specifically, micro-topography treatment of functional zones and their wetland units should be carried out on the premise of not reducing flood storage capacity, including: micro-modification of the terrain of each functional zone, so that the functional sub-zones located on the same side of the water distribution main channel meet the following requirements: the ground elevation of each sub-zone decreases along the water flow direction of the water distribution main channel; at the same time, micro-modification of the terrain of the wetland units in the sub-zones, so that the wetland units located on the same side of the same water inlet branch channel meet the following requirements: the ground elevation of each wetland unit decreases along the water flow direction of the water inlet branch channel. In some embodiments, the hydraulic gradient of the water distribution main channel and the water inlet branch channel is controlled to be no less than 0.1‰.

[0077] See also Figure 2 and Figure 4 , micro-topography transformation was carried out on the functional zones, and only the functional sub-zones LC-01, LC-02, LC-03, LC-04, and LC-05 located on the right side of the water distribution main channel 6 were subjected to micro-topography transformation. After the transformation, the average ground elevations of the functional sub-zones LC-01, LC-02, LC-03, LC-04, and LC-05 were 12.5m, 12.0m, 11.5m, 11.3m, and 11.0m respectively.

[0078] In the present application, the existing ridges are combined to separate the wetland units so that the wetland units are independent of each other; specifically, the ridges can be obtained by modifying the existing ridges or field paths, or they can be newly built. In some embodiments, the width of the ridge should not be less than 0.5m, and the height should be at least 0.3m higher than the water level of the wetland unit.

[0079] In this step, the water inlet and outlet structures are constructed according to the layout of the water inlet and outlet structures obtained in step (3), including: constructing an inlet culvert at the water inlet of each inlet branch canal, and constructing an outlet culvert at the water outlet of each outlet branch canal; constructing a waterfall weir in sections on each inlet branch canal; and setting an inlet culvert connected to the inlet branch canal and an outlet culvert connected to the outlet branch canal in each wetland unit.

[0080] Furthermore, the construction of water inlet and outlet structures also includes: constructing an inlet culvert at the water inlet of the water inlet branch channel contained in the sub-division according to the purifiable water volume of the sub-division, so that the amount of water entering the sub-division is not greater than the purifiable water volume; constructing an inlet culvert connected to the wetland unit according to the water distribution volume of each wetland unit, so that the amount of water entering the wetland unit is not greater than the water distribution volume of the wetland unit.

[0081] Furthermore, the construction of water inlet and outlet structures also includes: building a total water inlet culvert upstream of the external water system and connecting it to the water distribution main canal, and building a water outlet pump station downstream of the external water system and connecting it to the water outlet main canal. External water is drawn into the water distribution main canal by gravity through the total water inlet culvert, and the water out of the water outlet main canal is lifted and discharged to the external water system through the water outlet pump station.

[0082] When there are ponds in the existing ecological wetland flood storage area, the ecological restoration project in this step also includes: transforming the ponds into purification ponds, and connecting the purification ponds in series with the nearest inlet branch channel or outlet branch channel to play the water purification function. When connected in series with the inlet branch channel, the water entering the inlet branch channel first enters the purification pond for purification, and then flows into the inlet branch channel; when connected in series with the outlet branch channel, the water flowing out of the outlet branch channel first enters the purification pond for purification, and then is discharged.

[0083] When the ecological restoration project is completed, the ecological wetland flood storage area water purification system is constructed. In the ecological wetland flood storage area water purification system, the functional sub-divisions arranged along the flow direction of the water distribution main channel form an elevation difference. At the same time, the wetland units arranged along the flow direction of the water inlet branch channel also form an elevation difference. In this way, the water introduced through the water distribution main channel can flow evenly through all wetland units, realizing uniform water distribution in the entire area of ​​the ecological wetland flood storage area water purification system, thereby giving full play to the water purification effect of all wetland units, and at the same time significantly improving the purification efficiency.

[0084] (5) Based on the water quality of the inlet and outlet water of the ecological wetland flood storage area after the implementation of the ecological restoration project, evaluate whether the water quality purification effect of the ecological wetland flood storage area meets the preset requirements. If it does, the process ends; if it does not, execute step (6);

[0085] (6) Based on the inlet and outlet water quality of each wetland unit, evaluate whether the water purification effect of each wetland unit meets the preset requirements; optimize the ecological restoration project for wetland units that do not meet the preset requirements until the water purification effect of the wetland unit meets the preset requirements. The optimization of the ecological restoration project aims to improve the purification capacity of the wetland unit, including but not limited to the optimization of the vegetation configuration pattern.

[0086] When the wetland water quality purification effect is assessed as not meeting the standards, this application further evaluates the water purification effect of each wetland unit to identify wetland units with poor purification effects from a spatial level, and conducts targeted ecological restoration project optimization for the wetland units with poor purification effects, which can significantly reduce the amount of ecological restoration project optimization work and help improve the effect of ecological restoration project optimization.

[0087] This application is closely integrated with the existing topography and landforms of the flood storage area, relying on the existing farmland texture and pond water system in the flood storage area to layout and construct an ecological wetland flood storage area water quality purification system based on wetland units, using the least amount of engineering to ensure that waste water can flow through all areas of the flood storage area in space, and realize accurate water distribution of each wetland unit, and construct an ecological wetland flood storage area water quality purification system based on wetland units.

[0088] The ecological wetland flood storage area water purification system based on wetland units constructed in the present application includes an inlet unit, an outlet unit and a water purification area; the inlet unit includes a water distribution main channel and a plurality of inlet branch channels connected to the water distribution main channel; the outlet unit includes an outlet main channel and a plurality of outlet branch channels connected to the outlet main channel; the inlet branch channels and the outlet branch channels on the same side of the water distribution main channel are arranged alternately along the direction of the water distribution main channel;

[0089] The water purification area includes multiple functional zones, which are at least two of the forest and grassland wetland area, the paddy field wetland area, and the swamp wetland area. The functional zones may be the same or different; each functional zone is divided into functional sub-zones by the outlet branch canal it contains, and each functional sub-zone is divided into two patches by the inlet branch canal it contains, and each patch is divided into a number of independent wetland units distributed along the inlet branch canal direction by the ridge; each wetland unit is connected to the inlet branch canal and the outlet branch canal of the patch through the inlet culvert and the outlet culvert respectively;

[0090] The ground elevation of each functional sub-area located on the same side of the water distribution main canal decreases along the water flow direction of the water distribution main canal; the ground elevation of the wetland units located on the same side of the same water inlet branch canal decreases along the water flow direction of the water inlet branch canal.

[0091] Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the concept of the present application, all of which belong to the protection scope of the present application.

Claims

1. A method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit, characterized in that: include: (1) The wetland area is divided into functional zones, including water distribution main canals, multi-field wetland areas, swamp wetland areas, and forest and grassland wetland areas; (2) Analyze the soil nutrients in each functional zone, with the goal of reducing the release of endogenous pollution in the functional zone, and configure plants in each functional zone according to the soil nutrients; (3) Delineate wetland units in the field wetland area, marsh wetland area, and forest and grassland wetland area, and determine the water allocation for each wetland unit. On the premise of meeting the water inlet and outlet needs of each wetland unit, plan the scale and location of the wetland's water inlet and outlet structures; (4) Implementing ecological restoration projects in the wetland area according to steps (1) to (3); the implementation of ecological restoration projects at least includes the construction of functional zoning and wetland units, the construction of vegetation configuration projects, and the construction of water inlet and outlet buildings; (5) Based on the inlet and outlet water quality of the wetland after the implementation of the ecological restoration project, evaluate whether the water purification effect of the wetland area meets the preset requirements. If it does, the process ends; if it does not, proceed to step (6); (6) Based on the inlet and outlet water quality of each wetland unit, evaluate whether the water purification effect of each wetland unit meets the preset requirements; optimize the ecological restoration project for wetland units that do not meet the preset requirements until the water purification effect of the wetland unit meets the preset requirements; The wetland units delineated in the multi-field wetland area, the swamp wetland area and the forest and grassland wetland area include: (3.1) The existing ditches in the ecological wetland flood storage area are arranged into inlet and outlet branches, and the inlet and outlet branches on the same side of the water distribution main canal are arranged alternately along the direction of the water distribution main canal; (3.2) Use the outflow branch canals to divide each functional zone into sub-zones; (3.3) Divide the sub-region into two patches using the inlet canals contained in the sub-region, and further divide each patch into several small patches along the inlet canals, namely wetland units; The layout of the scale and location of the wetland water inlet and outlet structures includes: Arrange inlet culverts and outlet culverts at the inlet of the inlet branch canal and the outlet of the outlet branch canal respectively, and select inlet culverts and outlet culverts of appropriate scale according to the amount of purifiable water in the sub-district where the inlet branch canal and the outlet branch canal are located; Arrange waterfall weirs in sections on the water inlet branch channel; A plurality of inlet culverts corresponding to the respective wetland units are arranged and connected on the inlet branch channel, and a plurality of outlet culverts corresponding to the respective wetland units are arranged and connected on the outlet branch channel; The construction of the functional zones and their wetland units includes micro-topography processing of the functional zones and their wetland units, and constructing ridges to separate the wetland units so that the wetland units are independent of each other; The functional zones and their wetland units are processed with micro-topography, including: Micro-modification of the terrain of each functional zone is carried out so that the functional sub-zones on the same side of the water distribution main channel meet the following requirements: the ground elevation of each sub-zone decreases along the water flow direction of the water distribution main channel; The terrain of each wetland unit in the sub-division is slightly modified so that the wetland units located on the same side of the same inlet branch canal meet the following requirements: the ground elevation of each wetland unit decreases along the water flow direction of the inlet branch canal.

2. The method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit as claimed in claim 1, characterized in that: The amount of water that can be purified in the sub-district is the sum of the water allocations of all wetland units in the sub-district; The water distribution of the wetland unit adopts the preset target water distribution of the wetland unit or is predicted according to the maximum hydraulic load per unit area of ​​the wetland unit; The maximum hydraulic load per unit area of ​​the wetland unit is determined based on the wetland layout and the plant configuration obtained in step (2) in combination with engineering experience.

3. The method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit as claimed in claim 1, characterized in that: The construction of the water inlet and outlet buildings includes: An inlet culvert is constructed at the water inlet of each inlet branch canal, and an outlet culvert is constructed at the water outlet of each outlet branch canal; a waterfall weir is constructed in sections on each inlet branch canal; an inlet culvert connecting the inlet branch canal and an outlet culvert connecting the outlet branch canal are installed in each wetland unit.

4. The method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit as claimed in claim 3 is characterized by: The construction of the water inlet and outlet structures also includes: According to the purifiable water volume of the sub-district, build water inlet culverts at the water inlet of the water inlet branch channel contained in the sub-district, so that the water volume entering the sub-district is not greater than the purifiable water volume; According to the water distribution of each wetland unit, a water inlet culvert connected to the wetland unit is constructed so that the amount of water entering the wetland unit is not greater than the water distribution of the wetland unit.

5. The method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit as claimed in claim 3, characterized in that: The construction of the water inlet and outlet structures also includes: A main water inlet culvert is built upstream of the external water system and connected to the water distribution main canal. An outlet pumping station is built downstream of the external water system and connected to the outlet main canal.

6. The method for constructing a water purification system for an ecological wetland flood storage area based on a wetland unit as claimed in claim 1, characterized in that: When there are ponds in the existing ecological wetland flood storage area, the construction of the water inlet and outlet structures also includes: transforming the ponds into purification ponds, and connecting the purification ponds in series with the nearest water inlet main channel or water outlet main channel.

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