A method for constructing a sink circle of an inlet area of a shallow lake

Abstract

The present application relates to the technical field of hydraulic engineering, in particular to a method for constructing a lake absorption circle in a shallow lake entry area. The present application determines the dominant species of the water area by analyzing data; the main lake entry river is screened by sorting the lake entry and exit conditions, the river flow of the lake entry and exit, and the proportion of the river flow of the lake entry and exit. The lake shore area adjacent to the main lake entry river is connected to determine the main lake entry area of the river. The peripheral wave dissipation facilities, peripheral wave dissipation submerged dike, flow mud capture tank and dominant species are arranged at the position of the main lake entry area of the river away from the lake shore. The topography is reshaped and the local topography is lifted from the lake shore to the water body in the main lake entry area of the river, and the dominant species is planted along the slope from the lake shore. A front reservoir is formed by digging down at the entrance of each lake entry river, and a local flow resistance submerged dike is arranged; a flow guide groove is led out from the front reservoir, and a flow resistance submerged dike is arranged at the local turning position to form a lake absorption circle. The absorption circle can effectively reduce the adverse effects of the direct entry of river pollutants into the lake on the water quality of the lake body.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering technology, specifically a method for constructing a water absorption ring in the inflow area of ​​a shallow lake. Background Technology

[0002] Lakes are vital national resources, serving multiple functions including irrigation, regulating river runoff, supporting aquatic life, providing industrial and drinking water sources, and improving the regional ecological environment. They play a crucial role in national economic development. Surface waters such as rivers and streams within a watershed carry soil, organic matter, and nutrients into lakes. Simultaneously, industrial wastewater and domestic sewage from factories and cities within the watershed indirectly flow into lakes through rivers, negatively impacting their water quality. In the waters extending from the shoreline into the lake, the absorption ring plays a crucial role. It is the last line of defense against pollution entering the lake and a vital transition zone between the lake and its riparian zone. By collaboratively promoting habitat reshaping, ecological restoration, and production management, we can expand the scale of nearshore wetlands, optimize their structure, and enhance their capacity to intercept and treat pollutants entering the lake, thereby expanding the carrying capacity of the aquatic ecosystem and increasing aquatic biodiversity.

[0003] To overcome the shortcomings of existing technologies, this invention provides a method for constructing a water inflow zone in shallow lakes. Summary of the Invention

[0004] The purpose of this invention is to provide a method for constructing a water inflow zone in shallow lakes, in order to solve the problems in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A method for constructing a water inflow zone in a shallow lake includes the following steps:

[0007] Step 1: Based on historical vegetation data, investigate the aquatic vegetation species in the lake, identify aquatic plants with high occurrence frequency and high individual proportion, and identify them as the dominant species in the water area. Determine the dominant species of emergent plants, floating-leaved plants and submerged plants.

[0008] Step Two: Organize historical hydrological and water system data of the lake, compile the flow and inflow / outflow information of rivers flowing into and out of the lake, calculate the flow percentage of each river flowing into and out of the lake, and screen out the main rivers flowing into the lake; select a fixed time each month to conduct a complete hydrological year of lake-circling river flow monitoring, screen out the main rivers flowing into the lake based on the monitored flow data, and compare it with the collected lake-circling river information to identify and determine the main rivers flowing into the lake;

[0009] Step 3: Connect the lakeside areas adjacent to the main rivers flowing into the lake to determine the main river inflow areas;

[0010] Step 4: Install peripheral wave-damping facilities 0.8-1.2 km from the lake shore in the main river channel inflow area;

[0011] Step 5: Arrange multiple sections of the outer wave-dissipating submerged breakwater along the shore side of the outer wave-dissipating facility. The outer side of the outer wave-dissipating submerged breakwater connects with the outer wave-dissipating facility in Step 4. The sections of the outer wave-dissipating submerged breakwater are connected in an alternating manner, and mud capture troughs are arranged at the connection points.

[0012] Step Six: Plant the dominant emergent plant species on the top and shallow water areas of the outer wave-dissipating submerged dike, plant the dominant floating-leaved plant species along the riverbank on the slope towards the lake shore, and plant the dominant submerged plant species in the waters inside the outer wave-dissipating submerged dike.

[0013] Step 7: The main river channel flowing into the lake will undergo topographic reshaping and local topographic elevation from the lake shore to the water body, with the lake shore slope gradually transitioning to the lake bottom at a ratio of 1:200; at the same time, dominant species of emergent aquatic plants, floating-leaved plants and submerged plants will be planted along the lake shore slopes to form an aquatic plant community restoration zone in the water area between the lake shore and the outer wave-dissipating submerged dike.

[0014] Step 8: Deeply excavate the inlet of each river channel flowing into the lake to form a pre-reservoir. The pre-reservoir is set up in a fan shape from the river mouth towards the lake side. The outermost part of the pre-reservoir is raised to a higher elevation and a local flow-blocking submerged dike is set up to guide the water flowing into the lake towards the aquatic plant community restoration area. At the same time, a diversion channel is drawn out from the pre-reservoir, and a flow-blocking submerged dike is set up at the local bend of the diversion channel to form a lake absorption circle.

[0015] In a more optimized manner, in step three, the flow of the main river channel flowing into the lake accounts for 70-100% of the total flow into the lake; if there are individual rivers flowing into the lake that are separated from other main rivers flowing into the lake by multiple outflowing rivers and are far from the main river channel flowing into the lake, then such rivers can be disregarded.

[0016] In a more optimized manner, in step four, bamboo rafts are used for the external wave-dissipating facilities.

[0017] In a more optimized manner, in step five, the top elevation of the outer wave-dissipating submerged dike is level with the average annual water level of the lake, the top width is 50-80m, the slope ratio is 1:50, and the intermediate width connecting two adjacent sections of the outer wave-dissipating submerged dike is 100-300m.

[0018] In a more optimized manner, in step five, the depth of the mud capture channel is 2.0-3.0m, the width is 30-50m, and the length is greater than the middle width connecting two adjacent sections of the outer wave-dissipating submerged dike.

[0019] In a more optimized manner, in step six, the dominant species of emergent plants are those determined in step one, such as any one or more of reeds, cattails, and lotus; the dominant species of floating-leaved plants are those determined in step one, such as any one or more of water chestnuts, water hyacinths, and water lilies; and the dominant species of submerged plants are those determined in step one, such as any one or more of hornwort, giant water lily, and eelgrass.

[0020] Ideally, in step seven, the width of the lake shore slope where emergent vegetation is planted should be 50-100m.

[0021] In a more optimized manner, in step eight, the size of the pre-reservoir is related to the proportion of the river's flow. For the river with the largest flow, the pre-reservoir is 600-650m wide from the river mouth to the lake, while the size of the pre-reservoir for other rivers is reduced proportionally according to the flow proportion. The deepest part of the pre-reservoir is dug to a depth of 2.0-2.5m and transitions to the lake bottom with a 1:10 slope.

[0022] In a more optimized manner, in step eight, the width of the diversion channel is 30-80m and the depth is 1.0-2.0m; the diversion channel extends in an S-shape in the aquatic plant community restoration area.

[0023] In a more optimized manner, in step eight, the top elevation of the flow-blocking submerged dike is 10-20cm underwater, the slope ratio is 1:5, the top of the flow-blocking submerged dike is planted with dominant emergent plants, and the side slopes are planted with dominant floating-leaved plants.

[0024] The beneficial effects of this invention are:

[0025] This invention identifies the dominant species in a given water area by analyzing historical vegetation data. It then compiles historical hydrological and water system data for the lake, analyzes the flow rates and inflow / outflow patterns of rivers flowing into and out of the lake, calculates the flow rate percentage of each river, and identifies the main inflow rivers. The lakeside areas adjacent to these main inflow rivers are connected to define the main inflow areas. Furthermore, wave-dissipating facilities, submerged wave-dissipating dikes, sediment traps, and dominant species are installed at the lakeshore level within these main inflow areas. Topographic reshaping and localized elevation are implemented from the lakeshore into the water body within these main inflow areas. Simultaneously, dominant emergent, floating-leaved, and submerged plant species are planted along the lakeshore slopes, creating a restored aquatic plant community zone in the waters between the lakeshore and the submerged wave-dissipating dikes. A pre-reservoir is formed by excavating deep into the inlet of each river flowing into the lake. The outermost edge of the pre-reservoir is raised, and a localized flow-blocking submerged dike is installed to guide the inflow towards the aquatic plant community restoration area. Simultaneously, a diversion channel is led out from the pre-reservoir, and flow-blocking submerged dikes are installed at local bends in the channel, forming a lake absorption ring. A simplified diagram of the absorption ring structure of this invention is shown below. Figure 2 As shown, the cross-sectional view of the absorption ring structure of the present invention is as follows. Figure 1 As shown.

[0026] The key feature of this invention is that, through the above-mentioned methods, a lake absorption circle is formed within the inflow area of ​​a shallow lake. This effectively mitigates the adverse effects of pollutants directly entering the lake from the river on the lake's water quality. By leveraging the purification functions of different aquatic plants within the circle, the lake's water environmental capacity and quality are significantly improved. Simultaneously, with the gradual recovery of aquatic vegetation within the absorption circle, zooplankton, benthic animals, fish, and other organisms also gradually recover, enhancing the lake's ecological diversity, stability, and sustainability, and promoting the restoration of the ecosystem structure. Attached Figure Description

[0027] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0028] Figure 1 This is a cross-sectional view of the absorption ring structure of the present invention;

[0029] Figure 2 This is a simplified diagram of the absorption ring structure of the present invention;

[0030] Figure 3 The inflow volume (m³) of the main river channel flowing into the lake in Embodiment 1 of the present invention 3 ) and percentage (%);

[0031] Figure 4 This is a partial view of the Changdang Lake water absorption ring project according to Embodiment 1 of the present invention. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] A method for constructing a water inflow zone in a shallow lake includes the following steps:

[0034] Step 1: Based on historical vegetation data, investigate the aquatic vegetation species in the lake, identify aquatic plants with high occurrence frequency and high individual proportion, and identify them as the dominant species in the water area. Determine the dominant species of emergent plants, floating-leaved plants and submerged plants.

[0035] Step 2: Organize historical hydrological and water system data of the lake, organize the flow and inflow of rivers around the lake, calculate the flow ratio of each river entering and leaving the lake, and screen out the main rivers flowing into the lake.

[0036] Step 3: Connect the lakeside areas adjacent to the main rivers flowing into the lake to determine the main river inflow areas; the river flow in the main river inflow areas accounts for 70-100% of the total inflow into the lake.

[0037] Step 4: Install bamboo rafts as outer wave-dissipating structures in the main river channel flowing into the lake, 0.8-1.2 km from the lake shore;

[0038] Step 5: Arrange multiple sections of submerged outer wave-dissipating dikes along the shore side of the outer wave-dissipating facilities. The outer side of the submerged outer wave-dissipating dikes connects to the outer wave-dissipating facilities in Step 4. The sections of the submerged outer wave-dissipating dikes are connected in an alternating pattern, and mud-capping troughs are arranged at the connection points. The top elevation of the submerged outer wave-dissipating dikes is level with the average annual water level of the lake, the top width is 50-80m, the slope ratio is 1:50, and the width between adjacent sections of the submerged outer wave-dissipating dikes is 100-300m. The mud-capping troughs are 2.0-3.0m deep, longer than the width between adjacent sections of the submerged outer wave-dissipating dikes, and 30-50m wide.

[0039] Step Six: Plant dominant emergent plant species on the top and shallow water areas of the outer wave-dissipating submerged dike, plant dominant floating-leaved plant species along the riverbank on the slope towards the lake shore, and plant dominant submerged plant species in the waters inside the outer wave-dissipating submerged dike; among them, the dominant emergent plant species are those identified in Step One, such as any one or more of reeds, cattails, and lotus; the dominant floating-leaved plant species are those identified in Step One, such as any one or more of water chestnuts, water hyacinths, and water lilies; and the dominant submerged plant species are those identified in Step One, such as any one or more of hornwort, water caltrop, and eelgrass.

[0040] Step 7: In the main river channel flowing into the lake area, the topography is reshaped and locally raised from the lake shore to the water body, with the lake shore slope gradually transitioning to the lake bottom at a ratio of 1:200; at the same time, dominant species of emergent, floating-leaved, and submerged plants are planted along the lake shore slopes to form an aquatic plant community restoration zone in the water area between the lake shore and the outer wave-dissipating submerged dike; the planting width of the emergent plants is 50-100m.

[0041] Step 8: At the mouth of each river flowing into the lake, a pre-reservoir is dug deep to a depth of 2.0-2.5m, transitioning towards the lake bottom with a 1:10 slope. The pre-reservoir is fan-shaped from the river mouth towards the lake side, with the outermost edge of the pre-reservoir raised to a higher elevation. A local flow-blocking submerged dike is installed to guide the inflowing water towards the aquatic plant community restoration area. Simultaneously, a diversion channel with a width of 30-80m and a depth of 1.0-2.0m is led out from the pre-reservoir. The diversion channel extends in an S-shape in the aquatic plant community restoration area, with a flow-blocking submerged dike at a local bend, forming a lake absorption circle. The top elevation of the flow-blocking submerged dike is 10-20cm underwater, with a slope ratio of 1:5. The top of the flow-blocking submerged dike is planted with dominant emergent plant species, and the side slopes are planted with dominant floating-leaved plant species.

[0042] Historical hydrological and water system data of Changdang Lake: Changdang Lake, also known as Tao Lake, is one of the ten largest freshwater lakes in Jiangsu Province. Located in southern Jiangsu Province, upstream of the Taihu Lake basin, 9 km southeast of Jincheng Town, Jintan City, it lies between 31°30′ and 31°40′ north latitude and 119°30′ and 119°40′ east longitude. The lake is 8 km wide at its widest point east to west and approximately 16 km long north to south, spanning Jintan and Liyang cities. It is an important component of the Taihu Lake basin lake group. Changdang Lake is pear-shaped with a flat, unremarkable basin. The northern half of the basin is slightly deeper, while the southern half is shallower, with an average annual depth of about 1.0 m. It is a typical shallow, grassy lake, serving multiple functions including drinking water source, agricultural irrigation, flood control, and fisheries production. As an important part of the Tao-Ge water system, Changdang Lake's water source mainly comes from surface runoff and precipitation. Water supply: There are 44 rivers and canals of varying sizes flowing into and out of the lake area. Major inflow rivers include Dapu Port, Xinhe Port, Baishi Port, Sudu River, Xinjian River, and Beihe River; major outflow rivers include Huangli River, Beigan River, and Zhonggan River. The lake water flows eastward into Gehu Lake and then into Taihu Lake. Additionally, the Danjinli Canal and Qianzi Lake are closely related to Changdang Lake. Changdang Lake is a transient lake, and there are no hydraulic structures controlling its inflow and outflow rivers. Taking Changdang Lake as the research object, and addressing the issue of high levels of pollutants entering the lake and their potential direct adverse impact on the lake, this study proposes the construction of a western inflow area absorption zone. This zone will be constructed through engineering measures such as underwater submerged dikes for wave dissipation, diversion channels for flow guidance, and aquatic plant restoration. The aquatic plants will be used to purify the western inflow water, reducing its adverse impact on Changdang Lake.

[0043] Based on the above implementation method, the actual construction was carried out at Changdang Lake, and the specific process was as follows:

[0044] Example 1: Taking Changdang Lake as an example, by compiling long-term historical hydrological and water system data of Changdang Lake, the results show that the average annual water level of Changdang Lake is 3.47m, and the water system of Changdang Lake is determined to be westward inflow and eastward outflow. Based on the water volume data from the 2016 Changdang Lake survey (e.g., ... Figure 3As shown), the main rivers flowing into Changdang Lake are Dapu Port, Xinhe Port, Baishi Port, Sudu River, and Renhe Port. These have been selected as the main rivers flowing into the lake, and the lakeside areas adjacent to these main rivers have been connected to define the main river inflow areas. Figure 4 The area from Fangluo Port to Zhuangyang Port is shown in the diagram.

[0045] Step Two: Based on historical vegetation data, a survey of aquatic plant species in Changdang Lake was conducted. The results showed that in August 2011, among floating-leaved plants, water chestnut and water caltrop had the highest frequency of occurrence, both reaching 32.14%; among submerged plants, *Ceratophyllum demersum* and *Gnaphalium affine* had relatively high frequencies, at 28.57% and 25.00% respectively; among emergent plants, reeds and cattails had the highest frequencies. Data from the May 2012 survey showed that among floating-leaved plants, water caltrop and water chestnut had the highest frequencies, reaching 27.38% and 22.62% respectively; the frequency of submerged plants showed a decreasing trend. The frequencies of different plant types are shown in Table 1.

[0046] Table 1. Main species composition of aquatic plant communities in Changdang Lake

[0047]

[0048] Analysis of the main species composition table of aquatic plant communities in Changdang Lake leads to the following conclusions: When planting in Changdang Lake, the main floating-leaved plants are water chestnut, water caltrop, and water caltrop, while the main submerged plants are Vallisneria natans, goldfish algae, and giant water caltrop.

[0049] Step 3: Install bamboo rafts for wave dissipation 1 km from the lake shore in the main river inflow area, where the river flow in the main river inflow area accounts for 95% of the total inflow into the lake;

[0050] Step 4: Arrange multiple sections of submerged wave-dissipating dikes along the shoreside of the outer wave-dissipating facilities. The outer side of the submerged dikes connects to the outer wave-dissipating facilities in Step 3. The sections of the submerged dikes are connected in an alternating pattern, with mud capture troughs placed at the connection points. The outer wave-dissipating dikes are 1 km from the western shore, with an average width of 80 m, a top width of 50 m, a slope ratio of 1:50, and a top elevation that is the same as the average annual water level of Changdang Lake (3.47 m). In addition, considering the flood control issues of the inflowing rivers during the flood season, the outer wave-dissipating dikes are designed in 4 sections. The middle width between adjacent sections is 100 m, and the junctions of each section are staggered with a staggered width of 200 m. The mud capture troughs are 3.0 m deep, 400 m long, and 50 m wide. These mud capture troughs are used to collect particulate matter carried in the water flowing out from the connection points, including particulate matter containing adsorbed nitrogen and phosphorus nutrients.

[0051] Step 5: Plant the dominant emergent plant species, reeds and cattails, on the top of the outer wave-dissipating submerged dike and in the shallow water area of ​​the slope. The root system of the emergent plants can stabilize the outer wave-dissipating submerged dike and reduce wind and waves. Plant the dominant floating-leaved plant species, water chestnuts, water caltrops, and water hyacinths, on the slope towards the lake shore along the riverbank. Plant the dominant submerged plant species, Vallisneria natans, Ceratophyllum demersum, and Euphorbia tirucalli in the water area inside the outer wave-dissipating submerged dike.

[0052] Step Six: The main river channel flowing into the lake will undergo topographic reshaping and localized elevation from the lakeshore towards the water body, with the lakeshore slope gradually transitioning to the lakebed at a ratio of 1:200. Simultaneously, emergent aquatic plants such as lotus and cattails will be planted along the lakeshore slopes, with a width of 50 meters. This aims to improve the near-shore landscape while allowing the plant roots to absorb nitrogen and phosphorus nutrients from the water. Next, dominant floating-leaved plant species such as water chestnut, water caltrop, and water caltrop will be planted. These floating-leaved plants can be secured to specific areas using fencing to maintain their spatial position. Submerged plants such as Vallisneria natans and Ceratophyllum demersum will be planted near the floating-leaved plant area. An aquatic plant community restoration zone will be formed in the waters between the lakeshore and the surrounding wave-dissipating dikes.

[0053] Step Seven: Based on the inflow volume of each river into the lake as described in Step One, select the inflow outlets of Dapu Port, Baishi Port, Xinhe Port, Renhe Port, and Zhuangyang Port to excavate downwards to form pre-treatment reservoirs. The deepest point of the pre-treatment reservoirs should be 2.0m, with a 1:10 slope transitioning to the lake bottom. The pre-treatment reservoirs should be arranged in a fan shape from the river mouth towards the lake side, with the shape of the reservoirs determined by the existing topography and the direction of the inflow. Among them, the Dapu Port pre-treatment reservoir is the largest, with a length of 800m and a width of 200m along the water flow direction; Xinhe Port has a length of 850m and a width of 80m along the water flow direction; Baishi Port has a length of 500m and a width of 150m along the water depth; and Renhe Port and Zhuangyang Port have a length of 300m and a width of 120m along the water flow direction. Appropriate floating beds should be installed in the Dapu Port and Baishi Port pre-treatment reservoirs for water purification.

[0054] Step 8: The outermost edge of the pre-reservoir is raised to an elevation of 3.27m, and a partial flow-blocking submerged dike is constructed with a slope of 1:5. The top of the dike is planted with dominant emergent plants, and the side slopes are planted with dominant floating-leaved plants. The purpose of this partial flow-blocking dike is to guide the inflow of water towards the aquatic plant community restoration area. Simultaneously, a diversion channel with a width of 80m and a depth of 2.0m is drawn from the pre-reservoir. The channel extends in an S-shape within the aquatic plant community restoration area, and a flow-blocking submerged dike is constructed at the local bends of the channel, forming a lake absorption ring. The top elevation of the dike is 10cm underwater, and the slope ratio is 1:5. The detailed engineering layout of the Changdang Lake inflow absorption ring is as follows: Figure 4 As shown, the flow-blocking submerged dike and the outer wave-dissipating submerged dike can also be called underwater submerged beaches; in addition, ecological floating islands can also be set within the water storage range line when setting up this water absorption ring structure.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process method article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process method article or apparatus.

[0056] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing a absorption zone in the inflow area of ​​a shallow lake, characterized in that: Includes the following steps: Step 1: Based on historical vegetation data, investigate the aquatic vegetation species in the lake, identify aquatic plants with high occurrence frequency and high individual proportion, and identify them as the dominant species in the water area. Determine the dominant species of emergent plants, floating-leaved plants and submerged plants. Step 2: Organize historical hydrological and water system data of the lake, organize the flow and inflow of rivers around the lake, calculate the flow ratio of each river entering and leaving the lake, and screen out the main rivers flowing into the lake. Step 3: Connect the lakeside areas adjacent to the main rivers flowing into the lake to determine the main river inflow areas; Step 4: Install peripheral wave-damping facilities 0.8-1.2 km from the lake shore in the main river channel inflow area; Step 5: Arrange multiple sections of the outer wave-dissipating submerged breakwater along the shore side of the outer wave-dissipating facility. The outer side of the outer wave-dissipating submerged breakwater connects with the outer wave-dissipating facility in Step 4. The sections of the outer wave-dissipating submerged breakwater are connected in an alternating manner, and mud capture troughs are arranged at the connection points. Step Six: Plant the dominant emergent plant species on the top and shallow water areas of the outer wave-dissipating submerged dike, plant the dominant floating-leaved plant species along the riverbank on the slope towards the lake shore, and plant the dominant submerged plant species in the waters inside the outer wave-dissipating submerged dike. Step 7: The main river channel flowing into the lake will undergo topographic reshaping and local topographic elevation from the lake shore to the water body, with the lake shore slope gradually transitioning to the lake bottom at a ratio of 1:200; at the same time, dominant species of emergent aquatic plants, floating-leaved plants and submerged plants will be planted along the lake shore slopes to form an aquatic plant community restoration zone in the water area between the lake shore and the outer wave-dissipating submerged dike. Step 8: At the mouth of each river flowing into the lake, excavate downwards to form a pre-retention reservoir. The reservoirs should be arranged in a fan shape from the river mouth towards the lake side, with the outermost edge of the reservoir raised to a higher elevation. Construct localized flow-blocking submerged dikes to guide the inflow towards the aquatic plant community restoration area. Simultaneously, a diversion channel should be drawn from the reservoir, with flow-blocking submerged dikes at local bends to form a lake absorption ring. In step three, the river flow in the main inflow area accounts for 70-100% of the total inflow into the lake.

2. The method for constructing a water inflow zone in a shallow lake according to claim 1, characterized in that: In step four, bamboo rafts are used for the outer wave-dissipating facilities.

3. The method for constructing a water inflow zone in a shallow lake according to claim 1, characterized in that: In step five, the top elevation of the outer wave-dissipating submerged dike is level with the lake's average annual water level, the top width is 50-80m, the slope ratio is 1:50, and the intermediate width connecting two adjacent sections of the outer wave-dissipating submerged dike is 100-300m.

4. The method for constructing a water inflow zone in a shallow lake according to claim 1, characterized in that: In step five, the mud capture channel has a depth of 2.0-3.0m, a width of 30-50m, and a length greater than the width at the midpoint between two adjacent sections of the outer wave-dissipating submerged dike.

5. The method for constructing a water inflow zone in a shallow lake according to claim 1, characterized in that: In step six, the dominant species of emergent plants are those identified in step one, selected from any one or more of reeds, cattails, and lotus; the dominant species of floating-leaved plants are those identified in step one, selected from any one or more of water chestnuts, water hyacinths, and water caltrops; and the dominant species of submerged plants are those identified in step one, selected from any one or more of hornwort, giant water lily, and eelgrass.

6. The method for constructing a water inflow zone in a shallow lake according to claim 1, characterized in that: In step seven, the width of the emergent vegetation planted on the lake shore slope is 50-100m.

7. The method for constructing a water inflow zone in a shallow lake according to claim 1, characterized in that: In step eight, the deepest part of the pre-reservoir is dug to a depth of 2.0-2.5m, and a 1:10 slope is used to transition to the lake bottom.

8. The method for constructing a water inflow zone in a shallow lake according to claim 1, characterized in that: In step eight, the width of the diversion channel is 30-80m and the depth is 1.0-2.0m; the diversion channel extends in an S-shape in the aquatic plant community restoration area.

9. The method for constructing a water inflow zone in a shallow lake according to claim 1, characterized in that: In step eight, the top elevation of the flow-blocking submerged dike is 10-20cm underwater, the slope ratio is 1:5, the top of the flow-blocking submerged dike is planted with dominant emergent plants, and the side slopes are planted with dominant floating-leaved plants.

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