Intelligent prevention and control and gradient utilization system for non-point source pollution in low-hill mountainous area

Abstract

The invention provides a low-hill mountainous area non-point source pollution intelligent prevention and control and gradient utilization system, and relates to the technical field of low-hill mountainous area agricultural non-point source pollution prevention and control. The system comprises a drainage ditch, a water quality on-line monitoring module, an intelligent gate, a multi-stage ecological ditch pond, a direct drainage channel, an internet-of-things intelligent management and control platform and a stepped rice field. The system drives the intelligent gate to perform diversion according to a pollution index threshold value based on monitoring data, high-pollution water enters the multi-stage ecological ditch pond to be purified, low-pollution water is discharged through the direct discharge channel, and purified tail water is reused for the cascade rice field. Self-flow conveying is achieved by means of the regional height difference, a collaborative prevention and control mechanism of process interception, tail end purification and resource recycling is constructed, scientific prevention and control of pollution, intelligent management and efficient utilization of resources are achieved, the non-point source pollution treatment effect is remarkably improved, and continuous circulation of water and fertilizer resources is promoted.

Description

Technical Field

[0001] This invention relates to the field of agricultural non-point source pollution control technology in low hilly areas, and in particular to a smart control and cascade utilization system for non-point source pollution in low hilly areas. Background Technology

[0002] With the continuous increase in agricultural activities, non-point source pollution in low hilly and mountainous areas is becoming increasingly serious. This region has complex topography, a wide distribution, high ecological sensitivity, and concentrated rainfall, resulting in pollution occurring in tiers, with high frequency and variable migration paths. Traditional prevention and control methods focus primarily on scattered point treatment or end-of-pipe treatment, lacking a systematic approach and failing to cover contiguous tiered pollution areas. Resource utilization of eutrophic drainage is insufficient, leading to low water and fertilizer cycle efficiency. Management methods rely on manual labor, resulting in delayed response and limited precision. Furthermore, ecological synergy is weak, failing to fully utilize the self-purification and regulation functions of the natural ecosystem.

[0003] Therefore, the prevention and control of non-point source pollution in low hilly areas faces the dual goals of emission reduction and resource reuse. Existing technologies are insufficient to achieve both goals while maintaining long-term high efficiency and stability. There is an urgent need for a systematic solution that integrates process interception, end-of-pipe purification, and resource reuse, and possesses intelligent sensing and dynamic control capabilities. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a smart prevention and tiered utilization system for non-point source pollution in low-hilly areas. Based on intelligent control technology, it utilizes the elevation differences of surrounding paddy fields and ditches in low-hilly areas to form a collaborative prevention and control mechanism that includes process interception, end-of-pipe purification, and resource recycling. This system enables scientific pollution control, intelligent management, and efficient resource utilization in low-hilly areas, significantly improving the effectiveness of agricultural non-point source pollution control and promoting the sustainable use of water and fertilizer resources.

[0005] To achieve the above objectives, the present invention provides the following solution: A smart prevention and tiered utilization system for non-point source pollution in low hilly areas includes: drainage ditches, an online water quality monitoring module, intelligent gates, multi-level ecological ditches and ponds, a direct discharge channel, an IoT smart management and control platform, and tiered paddy fields. The drainage ditches are connected to the multi-level ecological ditches and ponds and the direct discharge channel. The online water quality monitoring module is deployed at monitoring locations to determine the water's destination and is linked to the intelligent gates. The intelligent gates are used to divert water based on preset pollution thresholds, diverting highly polluted water (below the threshold) into the multi-level ecological ditches and ponds for ecological purification, and discharging low-pollution water (above the threshold) into the direct discharge channel. The IoT smart management and control platform is communicatively connected to the online water quality monitoring module and the intelligent gates, processing the monitoring data from the online water quality monitoring module and generating control commands to implement diversion and irrigation / drainage control. The multi-level ecological ditches and ponds are used to ecologically purify the incoming highly polluted water, and the tiered paddy fields are connected to the outlet of the multi-level ecological ditches and ponds to receive purified wastewater for tiered reuse irrigation.

[0006] Preferably, the online water quality monitoring module includes a sampling system, a measurement system, a data processing and transmission system, and a power supply system; the sampling system is used to collect water samples, the measurement system is used to preprocess the water samples to obtain the monitoring data; the data processing and transmission system is used to transmit the monitoring data to the Internet of Things smart management and control platform to drive the smart gate; the power supply system includes photovoltaic solar panels and a large-capacity battery.

[0007] Preferably, the online water quality monitoring module is located at the end of the drainage ditch and at the outlet of the ecological pond.

[0008] Preferably, the intelligent gate includes a gate, a control system, sensors, and a communication system; the communication system is communicatively connected to the IoT smart management and control platform; the control system is used to open and close the gate according to control commands issued by the IoT smart management and control platform; the sensors include a water level sensor and a flow meter, the sensors are used to collect the water level and flow rate after the gate, and transmit them back to the IoT smart management and control platform to optimize irrigation and drainage strategies.

[0009] Preferably, the IoT smart management and control platform includes a data processing module, a control algorithm module, a communication module, and a user control interface; the data processing module is used to receive and process the monitoring data; the control algorithm module is used to generate control commands based on the monitoring data; the communication module is used to interact with the online water quality monitoring module and the smart gate for data and command exchange; the user control interface is used for remote monitoring and parameter setting to form a closed-loop control of monitoring, decision-making, and execution.

[0010] Preferably, the multi-level ecological ditch and pond is composed of multiple ecological ditches and ecological ponds connected in series according to the topographic height difference. The ecological pond is equipped with a flood discharge pipe and an ecological floating bed. The flood discharge pipe is used to regulate the water level, and the ecological floating bed is used to reduce pollution load and coordinate storage.

[0011] Preferably, the ecological ditch is equipped with dams at preset intervals along its course to slow down the flow and prolong the residence time, and an aquatic plant strip is arranged between two adjacent dams; the aquatic plants in the front section of the aquatic plant strip are used to intercept coarse particles and floating objects; the aquatic plants in the back section of the aquatic plant strip are used to intercept fine particles, and the aquatic plants are selected from at least one of canna lily, loosestrife, pickerelweed and yellow iris.

[0012] Preferably, the intelligent gates are respectively installed at the intersection of the direct discharge channel and the ecological ditch and at the inlet of the downstream terraced paddy fields.

[0013] Preferably, the terraced paddy field comprises multiple paddy field units connected in sequence, with the effluent from one paddy field unit serving as the influent to the next paddy field unit, thereby achieving the tiered reuse of purified wastewater and the recycling of water and fertilizer resources.

[0014] Preferably, the pollution index threshold is the Class III water quality limit for surface water. When the water quality reaches or exceeds Class III, the intelligent gate switches to the direct discharge channel. When the water quality is worse than Class III, the intelligent gate directs the water to the multi-level ecological ditches and ponds for purification.

[0015] The present invention discloses the following technical effects: 1. High-efficiency purification and nutrient resource recycling: This invention addresses the challenge of non-point source pollution control in contiguous farmland in low hilly areas by innovatively constructing a three-tiered ecological purification and resource recycling system: "ecological ditch - ecological pond - terraced paddy field". This technical system ecologically transforms existing ditches and ponds around farmland to form a composite ecological unit chain with gradient purification functions: the upstream ecological ditch achieves primary reduction of suspended solids and large particulate pollutants in runoff through physical interception and water flow regulation; the midstream ecological pond constructs a synergistic purification system of emergent-floating plant communities and rhizosphere microbial films, efficiently removing dissolved nitrogen and phosphorus pollutants through biological assimilation and microbial degradation; the downstream terraced paddy field system utilizes the terrain elevation difference to form multi-level cascading purification zones, achieving deep purification of pollutants through plant absorption, matrix adsorption, and denitrification, while the intercepted nitrogen and phosphorus nutrients are recycled for rice production through the irrigation system, constructing a closed-loop system for pollution control and nutrient recycling.

[0016] 2. "Intelligent" Management: This invention utilizes IoT technology and intelligent gates. The system automatically adjusts water flow based on real-time water quality monitoring data, enabling the automatic diversion of highly polluted water into ecological ditches for enhanced purification, precise diversion of low-pollution water through bypasses, and intelligent irrigation of purified effluent according to crop water requirements. The entire process requires no manual intervention, significantly reducing the frequency of manual inspections and sampling, and lowering operation and management costs. Simultaneously, through monitoring data feedback control, the system's response speed and stability to complex conditions such as rainfall runoff impacts and sudden load increases during peak fertilization periods are improved, ensuring that pollution reduction efficiency continuously meets design requirements.

[0017] 3. "Zero-power" operation: Relying on the original elevation potential energy of low hilly areas, the terraced field-ditch-pond combination is selected according to the terrain slope and hydrological confluence. After water level connection calculation, water flows into ditches, ponds and fields by gravity alone, without the need for electromechanical power and human energy consumption, thus achieving "zero-power" continuous and stable operation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart of a smart prevention and cascade utilization system for non-point source pollution in low hilly areas provided in an embodiment of the present invention; Figure 2 This is a layout diagram of a smart prevention and cascade utilization system for non-point source pollution in low hilly areas provided in an embodiment of the present invention; Figure 3 This is a layout diagram of the high-pollution water body treatment system of the intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas provided in an embodiment of the present invention.

[0020] Figure 4 The layout diagram of low-pollution water treatment for the intelligent prevention and cascade utilization system for non-point source pollution in hilly areas provided in this embodiment of the invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Reference Figure 1 , Figure 2 , Figure 3 and Figure 4 This invention provides a smart prevention and tiered utilization system for non-point source pollution in low hilly areas. It consists of drainage ditches, online water quality monitoring modules, smart gates, multi-level ecological ditches and ponds, direct discharge channels, an IoT smart management and control platform, and tiered paddy fields. It utilizes the height difference to transform the ditches and ponds surrounding contiguous farmland in low hilly areas, forming a three-level linkage system consisting of ecological ditches, ecological ponds, and tiered paddy fields. The drainage ditches are equipped with online water quality monitoring modules and smart gates to connect ecological ditches and ponds with direct discharge channels, realizing automatic interception and purification of highly polluted water and direct discharge of low-polluted water. Online water quality monitoring modules and smart gates are installed at the outlets of ecological ponds and the inlets of tiered paddy fields to realize water quality monitoring of purified tailwater and intelligent irrigation of tiered paddy fields. The IoT smart management and control platform connects to and manages the online water quality monitoring modules and smart gates, allowing water to flow naturally throughout the process.

[0024] Furthermore, the online water quality monitoring module includes a sampling system, a testing system, a data processing and transmission system, and a power supply system. The sampling system is used to collect water samples; the testing system is used to preprocess and test the collected water samples; the data processing and transmission system is used to transmit the test data to the IoT control platform; the power supply system includes photovoltaic solar panels and a large-capacity battery. The power supply system is located on the top of the equipment, and the photovoltaic solar panels generate electricity while the large-capacity battery stores electricity to ensure the normal operation of the equipment.

[0025] Furthermore, the intelligent gate includes a gate, a control system, sensors, a power supply system, and a communication system. Its communication is connected to an IoT smart management platform, which diverts water to multi-level ecological ditches or direct discharge channels based on pollution index thresholds. Simultaneously, it collects data such as water level and flow velocity through the gate for intelligent irrigation and drainage. The control system controls the opening and closing of the gate according to instructions from the IoT smart management platform. Sensors include water level sensors and flow meters to monitor the flow rate through the gate and the water level after the gate. The power supply module includes photovoltaic solar panels and a large-capacity battery. The power supply system is located on the top of the equipment, generating electricity from the photovoltaic solar panels and storing it in the large-capacity battery to ensure the normal operation of the equipment.

[0026] Furthermore, the multi-level ecological ditches and ponds are composed of multiple ecological ditches and ponds connected by the topographical height difference.

[0027] Furthermore, the direct discharge channel connects to nearby natural waterways for discharging low-pollution water and flood discharge.

[0028] Furthermore, the IoT smart management and control platform includes a data processing module, a control algorithm module, a communication module, and a user control interface; the data processing module is used to process the data from the online water quality monitoring module; the control algorithm module is used to generate control commands based on the processed data; the communication module is used to communicate with the online water quality monitoring module and the smart gate; and the user control interface is a mobile application used to display system status, remotely monitor, and receive user commands.

[0029] Furthermore, the terraced paddy fields consist of multiple paddy fields arranged in sequence, with each paddy field used to receive purified wastewater from the previous paddy field for irrigation.

[0030] Furthermore, a water-retaining dam is built at regular intervals in the ecological ditch to slow down the water flow. The same aquatic plant is planted in every two water-retaining dam areas. Tall plants are planted in the front section to intercept coarse particles of silt and debris such as branches, while fibrous-rooted plants with a higher density are planted in the back section to intercept fine particles of silt.

[0031] Furthermore, the ecological pond is equipped with a flood discharge pipe and an ecological floating bed. The flood discharge pipe is used to control the water level of the ecological pond, and the ecological floating bed is used to purify the water quality.

[0032] Furthermore, the system layout of this embodiment is as follows: (1) Connecting ditches, ponds and fields: Conduct on-site surveys of farmland to understand the topography, water sources, drainage conditions, etc. Utilize the elevation difference to connect existing terraced farmland, drainage ditches, ponds and natural rivers through ditches, so that farmland drainage and rainwater runoff can flow naturally, forming a three-level linkage system of ecological ditch-ecological pond-terraced paddy field; (2) Ecological Ditch Transformation: The ecological ditch mainly utilizes the existing drainage ditches in the area. Aquatic plants such as canna lilies, loosestrife, pickerelweed, and yellow iris are planted at the bottom of the ditch. A water-blocking dam is built every 50m to slow down the water flow. One type of aquatic plant is planted between every two water-blocking dams. The planting density of aquatic plants is approximately 30-40 plants / m. 2 ; (3) Ecological Pond Renovation: The ecological pond adopts a site-specific renovation strategy, ecologically reconstructing it based on the original hydrological characteristics. A modular ecological floating bed system is deployed on the surface of the pond. The floating bed plant configuration follows the principle of "function-driven, landscape-coordinated", selecting the highly efficient nitrogen and phosphorus absorbing species, *Myriophyllum spicatum*, as the core functional plant, and combining it with native landscape plants such as *Canna indica* and *Iris tectorum* to form a three-dimensional plant community. The number of ecological floating beds is adjusted according to system operation data to ensure the balance of the ecosystem and the water purification effect; (4) Equipment installation: Water quality online monitoring modules are installed at the end of the drainage ditch and the outlet of the ecological pond to continuously collect key indicators in the water body. The data is encrypted and transmitted to the Internet of Things platform for water quality trend analysis and intelligent gate linkage decision-making to ensure that the gate action can be triggered in time when the water quality is abnormal; Intelligent gates are installed at the intersection of the direct discharge channel and the front end of the ecological ditch and the downstream terraced paddy field inlet. The gates automatically adjust the water diversion according to the water quality-water level data fed back by the platform; The photovoltaic panels of the power supply system are all arranged facing due south and ensured that there are no shading objects to block the sunlight in order to maximize the photoelectric conversion efficiency. (5) Building an IoT smart management and control platform: Develop an IoT smart management and control platform to connect and manage the online water quality monitoring module and smart gate, and integrate sensor data, cloud algorithms and remote control functions to achieve intelligent control of the entire system.

[0033] Furthermore, the system operation mode of this embodiment is as follows: (1) Water collection: Farmland runoff and rainfall flow into drainage ditches under the action of gravity, and then flow through the online water quality monitoring module and the smart gate in sequence to realize the process of "monitoring first and then regulating".

[0034] (2) Intelligent monitoring and precise diversion: The system uses Class III surface water as the threshold to determine the water quality level in real time. If the water quality reaches or exceeds Class III, the gate will automatically switch to the direct discharge channel and the low-pollution water body will be safely discharged. If the water quality is worse than Class III, the gate will immediately turn to the ecological ditch and pond and the high-pollution water body will enter the subsequent purification path.

[0035] (3) Pollution interception, purification and resource reuse: The highly polluted water body is reduced in load through a three-stage process of "dilution-plant absorption-microbial degradation" in the ecological ditch and pond. The purified tailwater is then re-injected into the downstream terraced paddy fields as needed. The ecological ditch (front-end interception, rapid reduction of peak pollution), ecological pond (mid-end deep purification, water volume regulation), and terraced paddy fields (end-end resource utilization, nutrient recycling) form a closed-loop chain of "storage-purification-use", realizing zero direct discharge of pollution and efficient reuse of water resources.

[0036] Furthermore, the system maintenance method in this embodiment is as follows: (1) Establish a long-term monitoring mechanism: Regularly inspect and maintain the system to ensure its long-term stable operation. Regular inspections should focus on the water flow, the ecological environment of the ditches and farmland, and the condition of the facilities. During the inspection, promptly record any problems and abnormalities found, and take photos or videos to preserve evidence. The inspection records should be detailed and accurate to provide strong support for subsequent maintenance and repair. (2) Regular cleaning and harvesting of plants: During the operation of the ecological ditch, garbage, withered plants, fallen leaves, silt, etc. should be cleaned regularly to maintain the normal growth of plants and prevent the plants from rotting and affecting the treatment effect. Avoid the negative impact of withered plants on the water body. Harvest the plants 1-2 times a year. The harvesting time should be during the dormant period of the plants or after they wither. Regularly clean up the garbage and weeds in the ecological ditch to keep the water body of the ecological ditch clean. Regularly replenish aquatic animals such as fish to maintain the balance of the pond ecosystem. (3) Control of water level and plant density in ecological ditches and ponds: After heavy rain during the flood season, lower the water level in the ponds to reserve storage space; check the density of planted plants regularly, and divide or replant in areas with excessively high or low density to maintain the health of the plant community; based on the data obtained from system monitoring, consider whether it is necessary to increase the number of ecological floating beds in the ecological ponds. (4) Regularly calibrate the sensors: Regularly check the accuracy of the online water quality monitoring module and the intelligent gate detection. Before each rice planting season, calibrate the flow meter and water level sensor on site, and collect water samples at the same time to send them to the laboratory for analysis to compare and calibrate the water quality sensor, so as to ensure that the dual accuracy of water measurement and pollution index detection is always in the best operating state. (5) Maintenance and upkeep of facilities: Regularly assess the operating status of facilities, replenish the reagents required for the online water quality monitoring module on schedule, repair any abnormalities immediately, and replace vulnerable parts regularly to ensure the long-term stability and reliability of the system.

[0037] Taking a low-hilly mountainous area project in a county of a southern province as an example, the process and system of this invention were applied to construct a three-level linkage system of ecological ditch—ecological pond—terraced paddy fields for 600 mu of paddy fields (300 mu upstream and 300 mu downstream), achieving coordinated prevention and control of process interception, end-of-pipe purification, and resource recycling. In this case, the ecological ditch (200m long × 1.0m wide × 1.2m deep, with a dam every 40m) was planted with emergent plants such as canna lilies and canna lilies for initial interception; the ecological pond (4000m) 2The system employs both landscape-oriented and functional ecological floating beds (canna lilies, yellow irises, and green foxtail algae) to enhance nitrogen and phosphorus absorption. Terraced paddy fields utilize the terrain's elevation differences to construct a three-tiered cascading water purification unit, achieving deep end-of-pipe treatment and nutrient reuse. IoT technology and intelligent gates are integrated to automatically adjust diversion based on real-time water quality monitoring data, enabling precise interception and controllable discharge of water, thus achieving intelligent management of the entire "monitoring-decision-execution" process. Since its commissioning in April 2025, the system's monthly average concentrations of total nitrogen, ammonia nitrogen, and total phosphorus in the influent have been 2.5 mg / L, 1.1 mg / L, and 0.27 mg / L, respectively. After treatment, the removal rate has stabilized at 50%–65%, and the effluent meets the Class IV surface water standard. This has increased the regional agricultural non-point source pollution reduction rate by over 40% and improved water and fertilizer resource utilization by 30%, achieving low-cost, zero-energy pollution control and resource recycling goals. It provides a replicable technological paradigm for agricultural non-point source pollution control in the hilly areas of southern China.

[0038] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0039] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A smart prevention and cascade utilization system for non-point source pollution in low hilly areas, characterized in that, include: The system includes drainage ditches, an online water quality monitoring module, intelligent gates, multi-level ecological ditches and ponds, a direct discharge channel, an IoT smart management and control platform, and terraced paddy fields. The drainage ditches are connected to the multi-level ecological ditches and ponds and the direct discharge channel. The online water quality monitoring module is deployed at monitoring locations used to determine the flow of water and is linked to the intelligent gates. The intelligent gates are used to divert water based on preset pollution thresholds, diverting highly polluted water (below the threshold) into the multi-level ecological ditches and ponds for ecological purification, and discharging low-pollution water (above the threshold) into the direct discharge channel. The IoT smart management and control platform is communicatively connected to the online water quality monitoring module and the smart gate, and is used to process the monitoring data of the online water quality monitoring module and generate control commands to implement diversion and irrigation and drainage control; the multi-level ecological ditches and ponds are used to implement ecological purification of the incoming highly polluted water bodies, and the terraced paddy fields are connected to the outlet of the multi-level ecological ditches and ponds to receive the purified tailwater for tiered reuse irrigation.

2. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 1, characterized in that, The online water quality monitoring module includes a sampling system, a measurement system, a data processing and transmission system, and a power supply system. The sampling system is used to collect water samples, and the measurement system is used to preprocess the water samples to obtain the monitoring data. The data processing and transmission system is used to transmit the monitoring data to the Internet of Things smart management and control platform to drive the smart gate. The power supply system includes photovoltaic solar panels and a large-capacity battery.

3. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 1, characterized in that, The online water quality monitoring module is installed at the end of the drainage ditch and at the outlet of the ecological pond.

4. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 1, characterized in that, The intelligent gate includes a gate, a control system, sensors, and a communication system; the communication system is connected to the IoT smart management platform; the control system is used to open and close the gate according to the control commands issued by the IoT smart management platform; the sensors include a water level sensor and a flow meter, which are used to collect the water level and flow rate after the gate and transmit them back to the IoT smart management platform to optimize irrigation and drainage strategies.

5. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 1, characterized in that, The IoT smart management and control platform includes a data processing module, a control algorithm module, a communication module, and a user control interface. The data processing module is used to receive and process the monitoring data. The control algorithm module is used to generate control commands based on the monitoring data. The communication module is used to interact with the online water quality monitoring module and the smart gate for data and command exchange. The user control interface is used for remote monitoring and parameter setting to form a closed-loop control of monitoring, decision-making, and execution.

6. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 1, characterized in that, The multi-level ecological ditches and ponds are composed of multiple ecological ditches and ponds connected in series according to the topographical height difference. The ecological ponds are equipped with flood discharge pipes and ecological floating beds. The flood discharge pipes are used to regulate the water level, and the ecological floating beds are used to reduce pollution load and coordinate storage.

7. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 6, characterized in that, The ecological ditch is equipped with dams at preset intervals along its course to slow down the flow and prolong the residence time. Aquatic plant strips are arranged between adjacent dams. The aquatic plants in the front section of the aquatic plant strip are used to intercept coarse particles and floating objects. The aquatic plants in the back section of the aquatic plant strip are used to intercept fine particles. The aquatic plants are selected from at least one of canna lily, loosestrife, pickerelweed and yellow iris.

8. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 6, characterized in that, The intelligent gates are respectively installed at the intersection of the direct discharge channel and the ecological ditch, and at the inlet of the downstream terraced paddy fields.

9. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 1, characterized in that, The terraced paddy fields consist of multiple paddy field units connected in sequence. The effluent from one paddy field unit is used as the influent for the next paddy field unit, so as to realize the tiered reuse of purified wastewater and the recycling of water and fertilizer resources.

10. The intelligent prevention and cascade utilization system for non-point source pollution in low hilly areas according to claim 1, characterized in that, The pollution index threshold is the Class III water quality limit for surface water. When the water quality reaches or exceeds Class III, the intelligent gate switches to the direct discharge channel. When the water quality is worse than Class III, the intelligent gate directs the water to the multi-level ecological ditches and ponds for purification.

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