Method and device for efficiently collecting and storing lateral runoff of karst hillside surface karst zone

Abstract

The invention discloses a method and a device for efficiently collecting and storing lateral runoff of a karst slope surface karst zone. The method and the device are applied to efficiently collecting and storing rainfall flood runoff in a karst mountain area. A flexible concealed pipe water collection system is adopted and comprises a flexible concealed pipe water collection pipe with specifically designed water seepage holes, a ditch, a drainage pipeline, a water collection pipe outlet, biochar, a coarse and fine gravel filter material, a reservoir and the like. Each flexible concealed pipe is arranged in the ditch, water in the ditch is intensively discharged to an outlet of the water collecting pipe and is connected with the reservoir through the drainage pipeline, and the position of the ditch is higher than that of the reservoir connected with the ditch. According to the device, water and surface runoff in a surface karst zone can be effectively collected and transmitted, the hydrological driving force of water and soil loss is reduced, and meanwhile the utilization efficiency of rainfall flood resources of the high-permeability karst hillside is improved. The system is simple in structure and free of maintenance, can be widely applied to the slope toe part of the karst mountainous area, and assists in relieving the drought and water shortage problems of dispersed residential areas and economic fruit forest land parcels in the karst mountainous area.

Description

Technical Field

[0001] The invention relates to the technical field of soil and water conservation and efficient utilization of water resources, and in particular to a method and device for efficiently collecting and storing lateral runoff in the surface karst zone of a karst hillside, aiming at the arid karst rocky desertification area in the southwest. Background Art

[0002] Due to the complex terrain structure, the surface soil in the southwestern karst desertification area is relatively shallow, unevenly distributed and discontinuous, and the soil is eroded to varying degrees in the environment. In the southwestern karst area, despite the abundant rainfall, the surface water resources are seriously lost to the karst pores, a large amount of precipitation leaks into cracks, karst holes, underground rivers, and a large part of the water resources are lost to the lateral runoff of the shallow surface karst zone at the foot of the hillside. It is these various water resource loss pathways that lead to the lack of available surface water resources, serious water shortages and varying degrees of desertification in various regions, and it is difficult to meet the needs of agricultural irrigation, ecological restoration, animal husbandry, and temporary water use. How to effectively utilize the water resources of the shallow surface karst zone at the foot of the hillside to solve the water shortage problem in the southwestern karst area is one of the major problems facing the desertification and drought control. Traditional water collection methods are inefficient and it is difficult to fully utilize the natural water resources on the side of the shallow surface karst zone. The existing water collection devices mostly use simple hard pipe underground pipe water collection and drainage plus simple sedimentation tanks or filtration systems, but these systems have certain limitations in handling large amounts of sediment and maintenance. The method of collecting and draining lateral runoff from the surface karst zone of the hillside is a new method for utilizing lateral water resources in the shallow surface karst zone at the foot of the hillside. It usually refers to collecting lateral water resources in the shallow surface karst zone at the foot of the hillside for agricultural irrigation, ecological restoration, animal husbandry, temporary water use, etc. The unique above-ground and underground binary and three-dimensional structure of the karst area makes the key technologies of unconventional water utilization in non-karst areas inapplicable in this area. Actively developing a new model for efficient use of water resources that follows the special water cycle laws of karst areas is an effective measure to solve the problem of water shortage for production and life in remote and scattered settlements in karst areas where centralized water supply is difficult. It is also a feasible way to eliminate water limiting factors in the process of vegetation restoration and reconstruction and consolidate the results of comprehensive desertification control. In response to the above problems, we have developed a new flexible underground pipe water collection method that efficiently utilizes the lateral runoff of the shallow surface karst zone at the foot of the karst slope based on the characteristics of the rock and soil distribution pattern of the karst area and the existing understanding of the flow generation law of the karst slope interface. The present invention aims to provide an efficient, low-cost, and easy-to-maintain water collection method and device to solve the water shortage problem in the karst area and promote the effective use of water resources. It is committed to alleviating the problems of engineering and seasonal water shortages in karst mountainous areas and consolidating the results of vegetation restoration in desertification areas.

[0003] Karst landform is a landform with dissolution and deposition characteristics formed by soluble rocks, especially limestone, under the action of long-term water flow. This landform is widely distributed around the world, especially in southwest China. Karst areas are famous for their unique geological structure and hydrological characteristics, including natural landscapes such as underground rivers, caves, tiankengs, and peaks. The formation of karst landform is a complex natural process involving the long-term chemical dissolution of soluble rocks such as limestone by surface water and groundwater. This process leads to highly developed groundwater systems and rapid infiltration of surface water, forming unique hydrogeological conditions. Water resources in karst areas have obvious vertical zonation, and the conversion between surface water and groundwater is frequent. The distribution and availability of water resources are jointly affected by multiple factors such as topography, geology, and climate. However, the development and utilization of water resources in karst areas face a series of challenges. First, the high permeability of karst landforms makes it easy for surface water to be lost, making it difficult to form stable surface runoff, which brings difficulties to the collection and storage of water resources. Secondly, the complexity of groundwater systems increases the difficulty of water resource management and protection, especially in determining water sources and assessing water quality and quantity. In addition, the common soil erosion problem in karst areas further exacerbates the risk of water shortage. In the agricultural sector, the problem of water shortage in karst areas is particularly prominent. Due to the lack of surface water and the difficulty in using groundwater, traditional irrigation methods often cannot meet the needs of crop growth. In addition, the soil in karst areas is often thinner and less fertile, further limiting the potential for agricultural production. In view of the above challenges, innovative technologies and methods are needed for water resource management and protection in karst areas. This includes developing effective water collection systems, improving irrigation technology, and enhancing the sustainable use of water resources. These technologies and methods should fully consider the unique hydrogeological conditions in karst areas and their compatibility with local agricultural production practices.

[0004] In order to solve the problem of water resource collection and utilization in different spaces in the arid areas of karst rock desertification in the southwest, more and more research institutions and researchers have designed different water collection and storage methods and research explorations. For example, the Chinese patent with patent number: CN116557254A, a photovoltaic water collection and pumping method that utilizes climate resources in karst areas, including a gravity water storage device and a water storage irrigation device. The Chinese patent with patent number: CN103882908B describes a method for utilizing water resources in karst areas, including establishing a slope rainwater collection system, constructing a water lifting project, establishing a roof rainwater collection system, and promoting drip irrigation water-saving agricultural technology. The Chinese patent with patent number: CN108934658A designs a water collection and covering device for karst areas, which includes a film, a sink hole, a drainage rod, and a water collector, aiming to solve the problem that the roots of plants cannot effectively absorb water in the soil evaporation cycle. The Chinese patent with patent number CN202020122921.6 proposes a mountain water collection drip irrigation system designed specifically for the special geological and hydrological conditions in karst areas. The Chinese patent with patent number CN 116369159 A uses a karst ditch water collection pool, a gravity water collection pipe, a water collection and pumping device, a water pumping pipe and a water pumping storage irrigation device to collect precipitation and irrigate. The device is powered by solar energy and uses the height difference of the slope to achieve gravity and pumping. The Chinese patent with patent number CN 201210277217.8 uses naturally formed rock grooves as a water storage base, conducts anti-leakage water treatment, and forms a water storage unit. The Chinese patent with patent number CN201410111614.7 includes the establishment of a slope rain collection device, the construction of a water lifting project to develop subcutaneous water and upper stagnant water, a roof rain collection device, and the promotion of shallow irrigation water-saving agricultural technology and scientific irrigation methods. The Chinese patent with patent number: CN 201210100231.2 has developed a method for developing and utilizing groundwater resources in karst areas, which develops and utilizes groundwater resources through drilling, underground pipelines, etc.

[0005] With more and more research and invention, these technologies have solved the water collection and storage problem in karst areas to a certain extent, but there are some shortcomings: (1) The weather dependence problem and the applicable season and location of the photovoltaic water collection and pumping system are not explained and solutions are not given. For example, continuous cloudy days or rainy seasons may lead to reduced photovoltaic power generation efficiency. For example, the Chinese patent with patent number: CN116557254A only describes a photovoltaic water collection and pumping method that utilizes the climate resources in the karst area, including a gravity water storage device and a water storage irrigation device. However, the selected location has limited sunlight exposure time, or the geographical location is relatively harsh, and the water collection capacity is not ideal. It also does not have a certain wind resistance and collapse resistance and adaptability, and it is difficult to meet the needs of large-scale agricultural irrigation, ecological restoration, animal husbandry, and temporary water use. (2) Only the design depth and complexity are considered, but the construction cost and subsequent maintenance and operation costs are not considered. For example, the Chinese patent with patent number: CN103882908B, the complexity of its system technology may lead to high construction and operation costs. (3) It does not take into account the universal adaptability and the efficiency and convenience of the maintenance process. For example, the Chinese patent with patent number: CN108934658A may require special maintenance to ensure the integrity and function of the film covering device and fail to achieve the reasonable collection and multi-faceted utilization of water resources, which may cause water resource waste. (4) The design does not indicate that feasible solutions may be proposed for terrain adaptability problems and installation difficulties in actual construction. For example, the Chinese patent with patent number: CN202020122921.6 does not have a design that requires customized design and adjustment of water collection facilities and water pipelines to adapt to different terrain conditions due to the complex and changeable karst terrain. In terms of installation difficulty, since the rocks in the karst area are hard and have many cracks, the installation of water collection and drip irrigation facilities may require special construction technology and equipment. In terms of later maintenance, the special environment of the karst area may cause accelerated wear of system components, requiring more frequent maintenance and replacement, which increases long-term operating costs. (5) There is no proposal on how to reduce the initial investment and operating costs of the system, improve the efficiency of precipitation collection and reduce dependence on precipitation; how to adapt to the changing terrain conditions in the rocky desertification area and ensure the long-term stable operation of the system; how to ensure the stability of solar power supply and how to effectively manage and treat the collected precipitation. For example, the Chinese patent with patent number: CN 116369159 A, although providing an innovative water resource collection and utilization solution, has obvious disadvantages, including high initial investment and ongoing maintenance costs, the dependence of system efficiency on precipitation, and challenges in adaptability to complex terrain. In addition, the stability of solar power supply, the reasonable management of water resources and water quality assurance are also factors that need to be considered. The technical complexity requires a high level of construction and operation technology, and may have an impact on the local ecological environment. Summary of the invention

[0006] The first purpose of the present invention is to provide a high-efficiency lateral runoff collection and storage device in the surface karst zone of a karst hillside, which comprises an extendable flexible concealed pipe water collection pipe whose slope direction can be arbitrarily adjusted. The water in the ditch is filtered through multiple layers of coarse sand-adsorbable biochar-fine stone sand to achieve effective collection of water resources.

[0007] The second purpose of the present invention is to provide a method for efficiently collecting lateral runoff in the surface karst zone of a karst hillside, which is used to efficiently collect shallow surface lateral runoff water and can effectively gather a large amount of saturated and nearly saturated water in the shallow surface karst zone of the karst at a depth of about 0.5 to 1.5 m to meet the needs of agricultural irrigation, ecological restoration, animal husbandry, and temporary water use in local areas.

[0008] The specific technical solutions of the present invention are as follows:

[0009] A highly efficient lateral runoff collection and storage device for the surface karst zone of a karst hillside, which is composed of a flexible concealed pipe water collection system and a water storage tank, includes the following structures:

[0010] A ditch with a slope is arranged parallel to the selected contour line of the surface karst zone at the foot of the slope, and a concrete water collecting baffle is arranged in the vertical wall direction of the downslope position of the ditch;

[0011] The ditch has a depth of 1.2m to 1.5m, a width of 0.6m, a length of 8m to 10m, a slope of 2% to 5%, a height of 0.6m to 1.0m, and a designed thickness of 0.12m;

[0012] The bottom of the ditch has been treated for anti-seepage, and a concrete waterproof cushion layer with a thickness of 5cm to 10cm is arranged above the bottom of the ditch. Inside the ditch and above the concrete waterproof cushion layer, a coarse stone sand biochar backfill layer, a fine stone sand biochar filter layer and a backfill soil layer are arranged from bottom to top.

[0013] The coarse stone sand biochar backfill layer has a thickness of 20 cm to 40 cm, and the coarse stone sand biochar backfill layer uses adsorbable biochar with a particle size of 25 mm to 40 mm and coarse stone sand with a particle size of 5 mm to 25 mm;

[0014] The thickness of the fine stone sand biochar filter layer is 15 cm to 35 cm, and the fine stone sand biochar filter layer uses adsorbable biochar with a particle size of 15 mm to 25 mm and fine stone sand with a particle size of 0.15 to 2 mm; the thickness of the backfill soil layer is 65 cm to 85 cm;

[0015] A flexible concealed pipe is placed in series in the middle part of the coarse stone sand biochar backfill layer, and the pipe body of the flexible concealed pipe is provided with a funnel-shaped seepage hole; both ends of the flexible drainage concealed pipe are equipped with funnel water inlets, which help to guide more water into the pipe and prevent mud and sand from entering; the flexible concealed pipe guides the water to be discharged by connecting to the outlet of the collecting pipe.

[0016] The outlet of the water collecting pipe is connected to the drainage pipe, and the flexible concealed pipe is used to collect the seepage water flowing downward from the shallow surface layer at the foot of the slope and the shallow surface karst zone on the uphill slope.

[0017] The water reservoir structure comprises:

[0018] A plurality of (4-6) water outlets are arranged on the side of the water reservoir, and a water reservoir pressure drainage pipe and a water reservoir pressure drainage pipe valve are arranged on the lower part of the water reservoir wall on the same side of the water reservoir outlet; the water reservoir pressure drainage pipe also serves as a sand discharge pipe; the water reservoir outlet also serves as a flood overflow pipe; the water reservoir inlet is connected to collect water runoff of a flexible blind pipe through a drainage pipe; the drainage pipe is connected to the water reservoir inlet on the top of the external water reservoir, and the position of the pipe water collection system in the ditch is lower than the water reservoir connected thereto;

[0019] The water in the ditch passes through flexible concealed pipes, water collecting pipe outlets, and drainage pipes. When the amount of water entering the reservoir exceeds the storage capacity of the tank, the excess water is discharged through the overflow pipe of the gravity water tank. When sediment enters the reservoir, the valve of the reservoir sediment discharge pipe is opened to discharge the sediment.

[0020] A method for efficiently collecting and storing lateral runoff in the surface karst zone of a karst hillside, comprising the following steps:

[0021] 1. Dig a ditch with a depth of 1.2m to 1.5m, a width of about 0.6m, a length of 8m to 10m, and a slope of 2% to 5% at the shallow surface of the slope foot and parallel to the contour line. Perform anti-seepage treatment on the bottom of the ditch;

[0022] 2. A water collecting baffle made of concrete is set in the vertical wall direction of the downslope of the ditch; the height of the water collecting baffle is between 0.6m and 1.0m, and the designed thickness is 0.12m;

[0023] 3. Place a 5cm to 10cm concrete waterproof cushion at the bottom of the ditch after anti-seepage treatment, and lay a 20cm to 40cm thick coarse stone sand biochar backfill layer on top of the concrete waterproof cushion. The coarse stone sand biochar backfill layer uses adsorbable biochar with a particle size of 25mm to 40mm and coarse stone sand particles with a particle size of 5mm to 25mm;

[0024] 4. A flexible concealed pipe is placed in series about 3 cm to 5 cm above the bottom of the coarse stone sand biochar backfill layer. The pipe body of the flexible concealed pipe is provided with a funnel-shaped seepage hole; funnel water inlets are provided at both ends of the flexible concealed pipe, which helps to guide more water into the pipe and prevent sediment from entering; the flexible concealed pipe is connected to the outlet of the water collecting pipe to guide the water to discharge.

[0025] 5. A fine stone sand biochar filter layer with a thickness of 15 cm to 35 cm is laid on the coarse stone sand biochar backfill layer. The fine stone sand biochar filter layer uses adsorbable biochar with a particle size of 15 mm to 25 mm and fine stone sand particles with a particle size between 0.15 mm and 2 mm.

[0026] 6. A soil layer with a thickness of 65 cm to 85 cm is backfilled above the fine stone sand biochar filter layer; Steps 1-6 complete the installation of the pipeline water collection device.

[0027] 7. Connect the outlet of the collecting pipe described in step 4 to the drainage pipe, the drainage pipe is connected to the water inlet of the external water tank at the top, and the position of the pipe water collecting system in each ditch is lower than the water tank connected thereto; multiple water tank outlets are arranged on the side of the water tank, and a water tank pressure drain pipe and a water tank pressure drain pipe valve are arranged on the lower part of the water tank wall on the same side of the water tank outlet; the water tank pressure drain pipe also serves as a sand discharge pipe; the water tank outlet also serves as a spillway.

[0028] in,

[0029] Device design parameters Step 1: Collect multi-year meteorological data of the karst construction area of ​​the Hechi Huanjiang Research Station, including daily precipitation and the number of sunny days, as well as the time of the rainy and dry seasons;

[0030] Device design parameters step 2: Design flow calculation of flexible drainage concealed pipe system

[0031] Q=k·C·A (1)

[0032] Q is the design water flow (unit: cubic meters per second); k is the flow coefficient, which is determined according to the soil type and the characteristics of the drainage system; C is the runoff coefficient, which reflects the relationship between surface runoff and rainfall; A is the catchment area (unit: square kilometers)

[0033] Device design parameters step 3: Calculation of flexible drainage pipe diameter

[0034]

[0035] D is the diameter of the flexible drainage pipe (unit: meter); Q is the design flow rate (unit: cubic meter / second); π is the circumference, which is approximately 3.14 when calculated; u is the flow rate of water in the flexible drainage pipe (unit: meter / second), which is usually determined based on empirical values ​​and hydraulic calculations.

[0036] Compared with the prior art, the present invention has the following advantages and effects:

[0037] (1) The device of the present invention has the ability to collect runoff in multiple directions and at multiple levels. It uses flexible concealed pipe drainage technology to simultaneously collect surface runoff and lateral runoff from the surface karst zone, which can obtain water sources for a longer and more stable time and can also reduce soil erosion in the area.

[0038] (2) The device of the present invention can realize the natural collection of multi-interface runoff of the shallow karst system at the foot of the karst slope, and solves the problem that surface runoff and lateral runoff of the surface karst zone cannot be collected and utilized. It can realize agricultural irrigation or ecological restoration of any plot at the foot of the karst slope, and can solve the engineering water shortage and seasonal drought in the karst desertification area.

[0039] (3) The device of the present invention can ensure the consistency of the change trend of soil water potential at the foot of the slope before and after construction. After the flexible concealed pipe drainage system is installed, the excavated ditch soil is backfilled to restore the continuity of the change of the hydraulic gradient of the experimental area and the downslope and surrounding soils, thereby avoiding the cross section directly contacting the air and affecting the change trend of the slope soil water potential contour line.

[0040] (4) The concealed pipe drainage device of the present invention can effectively collect and transmit water and surface runoff in the karst zone, reduce soil erosion, and improve the collection and reuse efficiency of water resources. The system has a simple structure, low cost, easy maintenance, strong adaptability, and can be customized according to different karst landforms.

[0041] (5) Compared with the surface runoff water storage technology, this technology can obtain water source runoff for a longer time and can obtain surface runoff and surface lateral karst zone runoff at the same time, with more stable water volume and better water quality. Compared with the karst spring utilization technology, this technology can be implemented at the foot of any slope, is not limited to the location of the spring, and can be adjusted according to different geographical locations. Road rainwater storage technology depends on the density and hardening degree of the road, and this technology can also be implemented in areas without road distribution.

[0042] (6) This method and device has a short construction period and low construction cost. After careful systematic calculation, the total budget is about 4495.98 yuan per unit. The original slope vegetation and micro-topography will not be changed. The operation is stable and basically maintenance-free in the later stage is achieved. Compared with the traditional method of only storing surface runoff water, the water resource utilization efficiency at the foot of the slope is increased from 5% to more than 20%, the annual available water resource supply time is extended by more than 3 months, the water-soluble organic matter is 70% lower than that of surface water, and the water hardness is 55% lower than that of the lateral runoff water in the surface karst zone. The runoff water collected by this method is located in the lateral runoff of the surface karst zone at the foot of the slope. It has a certain slope and can realize self-flowing water collection and storage from top to bottom without the need for an external power system.

[0043] (7) The ditch in this device is used to collect and temporarily store surface runoff and lateral runoff from the surface karst zone, so that the water in the ditch can be collected and entered into the flexible concealed pipe. The water collection tank is set up to store the collected water resources, which can be used for agricultural irrigation, ecological water replenishment or other purposes. In order to further improve the water quality, a filter layer is also set up in the system to remove fine particles and impurities in the water. In addition, the system also uses adsorbable biochar with a particle size greater than 25mm. This material can effectively enhance the adsorption capacity of organic pollutants in water and prevent calcium carbonate sediments from clogging. Maintenance-free filler. Coarse and fine sand and gravel filter media are also used as filter media to improve the quality and efficiency of water filtration. The reservoir is established to store the collected water resources and allocate water resources or discharge sand through pressure drainage pipes and valves. The connecting pipe in the component is responsible for transporting the water collected by each pipeline water collection device to the reservoir. Valves play an important role in the entire system. They are used to control the water level of the reservoir and adjust the water storage volume. Water collection baffles are set up when necessary to optimize the water flow direction and improve water collection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 : A schematic diagram of the principle of a method for efficiently collecting and storing lateral runoff in the surface karst zone of a karst hillside;

[0045] Figure 2 : A schematic diagram of the overall structure of a highly efficient lateral runoff collection and storage device for the surface karst zone of a karst hillside;

[0046] Figure 3 : A schematic diagram of a general cross-sectional structure of a ditch of the present invention;

[0047] Figure 4 : Schematic diagram of the ditch structure of the present invention;

[0048] Figure 5 : Side and front schematic diagram of flexible drainage concealed pipe structure;

[0049] Figure 6 : Schematic diagram of the device structure and position relationship of the present invention;

[0050] Figure 7 : Schematic diagram of the water reservoir structure of the present invention;

[0051] Among them, 1-flexible concealed pipe, 2-tee joint, 3-water collecting pipe outlet, 4-drainage pipe, 5-water inlet of reservoir, 6-water reservoir, 7-water outlet of reservoir, 8-pressure drain pipe, 9-pressure drain pipe valve, 10-water collecting baffle, 11-ditch, 12-backfill soil layer, 13-fine stone sand biochar filter layer, 14-coarse stone sand biochar backfill layer, 15-concrete waterproof cushion layer, 16-seepage hole, 17-funnel water inlet. DETAILED DESCRIPTION

[0052] The device of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0053] Example

[0054] like Figures 1 to 7 As shown, a karst hillside surface karst zone lateral runoff high-efficiency collection and storage device is composed of a flexible concealed pipe water collection system and a reservoir, including the following structures:

[0055] A ditch 11 with a slope is arranged parallel to the selected contour line of the surface karst zone at the foot of the slope, and a concrete water collecting baffle 10 is arranged in the vertical wall direction of the downslope position of the ditch 11;

[0056] The ditch 11 is 1.5m deep, 0.6m wide, 10m long, and has a slope of 3%. The water collecting baffle 10 is 1.0m high and has a designed thickness of 0.12m.

[0057] The bottom of the ditch 11 has been treated for anti-seepage, and a concrete waterproof cushion layer 15 with a thickness of 10 cm is arranged above the bottom of the ditch 11. Inside the ditch 11 and above the concrete waterproof cushion layer 15, a coarse stone sand biochar backfill layer 14, a fine stone sand biochar filter layer 13 and a backfill soil layer 12 are arranged from bottom to top.

[0058] The thickness of the coarse stone sand biochar backfill layer 14 is 40 cm, and the coarse stone sand biochar backfill layer 14 uses adsorbable biochar with a particle size of 25 mm to 40 mm and coarse stone sand with a particle size of 5 mm to 25 mm;

[0059] The thickness of the fine stone sand biochar filter layer 13 is 35 cm, and the fine stone sand biochar filter layer 13 uses adsorbable biochar with a particle size of 15 mm to 25 mm and fine stone sand with a particle size of 0.15 to 2 mm; the thickness of the backfill soil layer 12 is 70 cm;

[0060] A flexible concealed pipe 1 is placed in series in the middle part of the coarse stone sand biochar backfill layer 13, which is used to collect seepage water flowing downward from the shallow surface layer at the foot of the slope and the shallow surface karst zone on the uphill slope; the pipe body of the flexible concealed pipe 1 is provided with funnel-shaped seepage holes 16; both ends of the flexible concealed pipe 1 are equipped with funnel water inlets 17, which help to guide more water into the pipe and prevent mud and sand from entering; the flexible concealed pipe 1 guides the water flow to be discharged by connecting to the water collecting pipe outlet 3.

[0061] The water reservoir structure comprises:

[0062] Four water tank outlets 7 are arranged on the side of the water tank 6, and a water tank pressure drain pipe 8 and a water tank pressure drain pipe valve 9 are arranged on the lower part of the water tank wall on the same side of the water tank outlet 7; the water tank pressure drain pipe 8 also serves as a sand discharge pipe; the water tank outlet 7 also serves as a spillway; the water tank inlet 7 is connected to the water runoff of the flexible concealed pipe 1 through a drainage pipe 4; one end of the drainage pipe 4 is connected to the water collecting pipe outlet 3, and the other end of the drainage pipe 4 is connected to the water tank inlet 5, and the position of the pipe water collecting system in the ditch 11 is lower than the water tank 6 connected thereto.

[0063] A method for efficiently collecting and storing lateral runoff in the surface karst zone of a karst hillside, comprising the following steps:

[0064] 1. A ditch 11 with a depth of 1.5m, a width of about 0.6m, a length of 10m, and a slope of 3%3 is excavated in the shallow surface layer at the foot of the slope parallel to the contour line, with high sides and low middle. The bottom of the ditch 11 is treated for seepage prevention;

[0065] 2. A water-collecting baffle 10 made of concrete is set in the vertical wall direction of the downslope position of the ditch 11 after anti-seepage treatment; the water-collecting baffle 10 has a height of 1.0m and a designed thickness of 0.12m; and the concrete water-collecting baffle 11 is hardened and then demolded;

[0066] 3. After step 2 is completed, a 10 cm thick concrete waterproof cushion layer 15 is set at the bottom of the ditch 11, and a 40 cm thick coarse stone sand biochar backfill layer 14 is laid on top of the concrete waterproof cushion layer 15;

[0067] 4. A flexible concealed pipe 1 is placed in series in the middle part of the coarse stone sand biochar backfill layer 14, and the pipe body of the flexible concealed pipe 1 is provided with a funnel-shaped seepage hole 16; both ends of the flexible concealed pipe 1 are provided with a funnel water inlet 17, which helps to guide more water into the pipe and prevent mud and sand from entering; the flexible concealed pipe 1 is connected to the water collecting pipe outlet 3 to guide the water to discharge.

[0068] 5. A fine stone sand biochar filter layer 13 with a thickness of 35 cm is laid on the coarse stone sand biochar backfill layer 14. The fine stone sand biochar filter layer 13 uses adsorbable biochar with a particle size of 15 mm to 25 mm and fine stone sand particles with a particle size of 0.15 to 2 mm;

[0069] 6. A 70 cm thick original backfill soil layer 12 is laid on top of the fine stone sand biochar filter layer 13;

[0070] The above steps 1-6 complete the setup and installation of the pipe water collection device.

[0071] 7. Connect the water collecting pipe outlet 3 described in step 4 to the drainage pipe 4, and the drainage pipe 4 is connected to the water tank inlet 5 on the top of the external water tank 6 to collect the water runoff of the flexible concealed pipe 1; and the position of the pipe water collecting system in the ditch 11 is lower than the water tank 6 connected thereto; a plurality of water tank outlets 7 are arranged on the side of the water tank 6, and a water tank pressure drain pipe 8 and a water tank pressure drain pipe valve 9 are arranged on the lower part of the water tank wall on the same side of the water tank outlet 7; the water tank pressure drain pipe 8 also serves as a sand discharge pipe; and the water tank outlet 7 also serves as a spillway.

[0072] in,

[0073] Device design parameters Step 1: Collect multi-year meteorological data of the karst construction area of ​​the Hechi Huanjiang Research Station, including daily precipitation and the number of sunny days, as well as the time of the rainy and dry seasons;

[0074] Device design parameters step 2: Design flow calculation of flexible drainage concealed pipe system

[0075] Q=k·C·A (1)

[0076] Q is the design water flow (unit: cubic meters per second); k is the flow coefficient, which is determined according to the soil type and the characteristics of the drainage system; C is the runoff coefficient, which reflects the relationship between surface runoff and rainfall; A is the catchment area (unit: square kilometers)

[0077] Device design parameters step 3: Calculation of flexible drainage pipe diameter

[0078]

[0079] D is the diameter of the flexible drainage pipe (unit: meter); Q is the design flow rate (unit: cubic meter / second); π is the value of the circumference, which is approximately 3.14 during calculation; u is the flow rate of water in the flexible drainage pipe (unit: meter / second), which is usually determined based on empirical values ​​and hydraulic calculations.

[0080] like Figure 3As shown, a schematic diagram of the detailed construction of the general cross-sectional structure of the ditch 11 is shown. The ditch 11 plays the role of gathering and intercepting surface runoff and shallow lateral karst zone runoff. The spatial organizational structure of the ditch 11 from top to bottom includes a primary backfill soil layer 12 of about 65cm to 85cm, a fine stone sand biochar filtration layer 13 of 15cm to 35cm, a coarse stone sand biochar backfill layer 14 of 20cm to 40cm, a 5cm to 10cm concrete waterproof cushion layer 15, and a flexible drainage concealed pipe 1 is arranged about 3cm to 5cm above the concrete waterproof cushion layer 15. Funnel water inlet holes 17 are respectively arranged at both ends of the flexible drainage concealed pipe 1. There are also seepage holes 16 on the side and upper part of the flexible drainage concealed pipe 1 for gathering surface runoff and shallow karst zone lateral runoff. The downslope position on the side of the flexible drainage concealed pipe 1 is a water collecting baffle 10. The arrangement of the flexible pipe 1 should be determined from high to low according to the actual on-site slope and the water runoff convergence point, and the connection drainage position of the flexible concealed pipe 1 and the water collecting pipe 3 is determined from high to low.

[0081] Figure 4 The basic structural schematic diagram of the ditch 11 is shown, including a cross section of the ditch 11, showing the bottom of the ditch 11, the slope on the uphill side, the concrete water collecting baffle 10 on the downhill vertical wall, and the top structure. The ditch 11 has a specific slope to facilitate the smooth flow of water. The direction of water flow is that the flexible drainage pipes 1 on both sides converge and discharge to the middle water collecting pipe 3.

[0082] Figure 5The structural design of the flexible drainage concealed pipe 1 is shown in detail. The flexible drainage concealed pipe 1 is a key component of the system of the present invention, especially in areas such as karst landforms. They can effectively collect surface runoff and guide lateral runoff from the surface karst zone, especially the seepage holes 16 and the funnel inlets 17 at both ends. The seepage holes 16 are funnel-shaped small holes on the flexible drainage concealed pipe 1 that allow water to enter the pipe. These holes are usually evenly distributed on the upper and side sides of the pipe and arranged around the entire circumference of the pipe. The size and distribution density of the seepage holes 16 may be adjusted according to design requirements and water flow to optimize water collection efficiency. The flexible drainage concealed pipe 1 is equipped with funnel inlets 17 at both ends. This design helps to guide more water into the pipe. The funnel inlet has a larger opening that gradually narrows as it goes deeper into the pipe, which can reduce turbulence and sediment when the water enters. The flexible drainage concealed pipe is made of flexible materials, such as rubber, plastic or other synthetic materials, which can adapt to uneven settlement of the ground and reduce the risk of pipe rupture. The flexible drainage concealed pipe of the present invention has a special connection design. The flexible drainage pipe can be closely fitted with the bottom of the ditch and the exposed surface of the irregular weathered rock layer, allowing the pipe to extend and turn in different directions to improve the water collection efficiency. In order to prevent larger solid particles and plant roots from entering the pipe and blocking the seepage holes, a filter screen or grid may be installed at the water inlet of the flexible drainage concealed pipe according to the soil conditions and soil erosion capacity. Considering the chemical properties of the underground environment, the flexible concealed pipe needs to have anti-corrosion properties to ensure long-term stable operation.

[0083] This application also provides relevant attachments: "Budget for Concealed Pipe Drainage System and Device Engineering in Karst Surface Karst Zone" shows the overall cost budget cost analysis list of the present invention through calculation. The project is the construction of a karst hillside surface karst zone lateral runoff efficient collection and storage method and device of the present invention, involving two main parts: civil engineering and installation. The total cost budget of the project is 4495.98 yuan, and the price information of labor, materials and machinery is taken from the information price of Hechi City in March 2024. The budget cost of the civil engineering part is 3008.49 yuan, which includes the total price of the sub-items and the unit price measure item list of 2321.48 yuan, of which the provisional estimate is the same value. In addition, the total price measure item list is priced at 168.12 yuan, covering the safety and civilized construction fee of 153.71 yuan. The budget cost of the installation part is RMB 1,487.49, of which the total price of the sub-items and the unit price measures list is RMB 1,121.22, and the provisional price is also RMB 1,121.22. The total price measures list is RMB 84.73, including RMB 61.42 for safety and civilized construction. The total fees for the project are RMB 429.20, and the total value-added tax is RMB 371.23. These costs reflect the additional costs of the project in compliance with relevant laws and policies. From an economic perspective, the budget cost of the project is relatively clear, which helps to reasonably allocate funds and control costs. The safety and civilized construction fee is included in the budget, which shows the importance of construction safety and environmental protection. In addition, the clearly listed fees and value-added tax help the project in terms of tax planning and compliance. The subdivided budget items help track and control costs at each stage of the project. With accurate budget allocation, resource use can be optimized, waste can be reduced, and adjustments can be made when necessary. In summary, the cost budget for the karst surface karst zone underground pipe drainage system is RMB 4495.98, covering civil engineering, installation, fees and VAT. This budget provides a detailed cost overview for the project, which helps with cost control and resource optimization.

Claims

1. A highly efficient lateral runoff collection and storage device for the surface karst zone of a karst hillside, characterized in that: Including ditches (11) and reservoirs (6): The ditch (11) is arranged parallel to the selected contour line of the surface karst zone at the foot of the slope, and a concrete water collection baffle (10) is arranged at the downslope position and in the vertical wall direction of the ditch (11); the bottom of the ditch (11) has been treated for anti-seepage, and a concrete waterproof cushion layer (15) is arranged above the bottom of the ditch (11); inside the ditch (11) and above the concrete waterproof cushion layer (15), a coarse stone sand biochar backfill layer (14), a fine stone sand biochar filter layer (13) and a backfill soil layer (12) are arranged from bottom to top; A flexible concealed pipe (1) is placed in series in the middle of the coarse sand biochar backfill layer (13); the pipe body of the flexible concealed pipe (1) is provided with a funnel-shaped water seepage hole (16); both ends of the flexible concealed pipe (1) are provided with a funnel water inlet (17), and the flexible concealed pipe (1) guides water flow to be discharged by connecting to the water collection pipe outlet (3); The side of the water reservoir (6) is provided with 4 to 6 water reservoir outlets (7); the lower part of the water reservoir wall on the same side as the water reservoir outlet (7) is provided with a water reservoir pressure drainage pipe (8) and a water reservoir pressure drainage pipe valve (9); the water reservoir pressure drainage pipe (8) also serves as a sand discharge pipe; the water reservoir outlet (7) also serves as a flood overflow pipe; the water reservoir inlet (7) is connected to the water collection pipe (1) through a drainage pipe (4); one end of the drainage pipe (4) is connected to the water collection pipe outlet (3), and the other end of the drainage pipe (4) is connected to the water reservoir inlet (5), and the position of the pipe water collection system in the ditch (11) is lower than the water reservoir (6) connected thereto.

2. The device for efficiently collecting and storing lateral runoff in the surface karst zone of a karst hillside according to claim 1, characterized in that: The ditch (11) has a depth of 1.2m to 1.5m, a width of 0.6m, a length of 8m to 10m, and a slope of 2% to 5%. The water collecting baffle (10) has a height of 0.6m to 1.0m and a thickness of 0.12m.

3. The device for efficiently collecting and storing lateral runoff in the surface karst zone of a karst hillside according to claim 1, characterized in that: The thickness of the concrete waterproof cushion layer (15) is 5 cm to 10 cm; the thickness of the fine stone sand biochar filter layer (13) is 15 cm to 35 cm, and the fine stone sand biochar filter layer (13) uses adsorbable biochar with a particle size of 15 mm to 25 mm and fine stone sand with a particle size of 0.15 to 2 mm; the thickness of the backfill soil layer (12) is 65 cm to 85 cm; the thickness of the coarse stone sand biochar backfill layer (14) is 20 cm to 40 cm, and the coarse stone sand biochar backfill layer (14) uses adsorbable biochar with a particle size of 25 mm to 40 mm and coarse stone sand with a particle size of 5 mm to 25 mm.

4. A method for efficiently collecting and storing lateral runoff in the surface karst zone of a karst hillside, characterized in that: The steps include: 1) digging a ditch (11) with a depth of 1.2m to 1.5m, a width of 0.6m, a length of 8m to 10m, a high side and a low middle with a slope of 2% to 5% in the shallow surface layer at the foot of the slope parallel to the contour line, and performing anti-seepage treatment on the bottom of the ditch (11); 2) a water collecting baffle (10) made of concrete is arranged in the vertical wall direction of the downslope position of the ditch (11) after anti-seepage treatment; the water collecting baffle (10) has a height of 0.6m to 1.0m and a designed thickness of 0.12m; and the concrete water collecting baffle (11) is hardened and the formwork is removed; 3) a concrete waterproof cushion layer (15) is provided at the bottom of the ditch (11) described in step 2), and a coarse stone sand biochar backfill layer (14) with a thickness of 20 cm to 40 cm is laid on the concrete waterproof cushion layer (15), wherein the coarse stone sand biochar backfill layer (14) uses adsorbable biochar with a particle size of 25 mm to 40 mm and coarse stone sand particles with a particle size of 5 mm to 25 mm; 4) A flexible concealed pipe (1) is placed in series in the middle part of the coarse stone sand biochar backfill layer (14), and the pipe body of the flexible concealed pipe (1) is provided with a funnel-shaped water seepage hole (16); both ends of the flexible concealed pipe (1) are provided with a funnel water inlet (17), which helps to guide more water flow into the pipe and prevent sediment from entering; the flexible concealed pipe (1) is connected to the outlet of the water collecting pipe (3) to guide the water flow to be discharged. 5) A fine stone sand biochar filter layer (13) with a thickness of 15 cm to 35 cm is laid on the coarse stone sand biochar backfill layer (14); the fine stone sand biochar filter layer (13) uses adsorbable biochar with a particle size of 15 mm to 25 mm and fine stone sand particles with a particle size of 0.15 to 2 mm; 6) A native backfill soil layer (12) with a thickness of 65 cm to 85 cm is laid on the fine stone sand biochar filter layer (13); 7) The water collecting pipe outlet (3) of step 4) is connected to the drainage pipe (4), and the drainage pipe (4) is connected to the water tank inlet (5) at the top of the external water tank (6) to collect the water runoff of the flexible concealed pipe (1); and the position of the pipe water collecting system in the ditch (11) is lower than the water tank (6) connected thereto; a plurality of water tank outlets (7) are arranged on the side of the water tank (6), and a water tank pressure drain pipe (8) and a water tank pressure drain pipe valve (9) are arranged on the lower part of the water tank wall on the same side as the water tank outlet (7); the water tank pressure drain pipe (8) also serves as a sand discharge pipe; and the water tank outlet (7) also serves as a flood overflow pipe.

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