A method for water storage in landscaping

Abstract

The application provides a kind of garden greening water storage method, and relates to the technical field of garden greening ecological engineering.The garden greening water storage method comprises the following steps: step S1, topographic survey and point optimization design: topographic survey is carried out on the target greening area, a digital elevation model is established, and differential hole distribution design is carried out according to the topographic features such as slope, slope direction, catchment line and depression; step S2, in-situ drilling and hole wall reinforcement: in-situ drilling is carried out using a spiral drill, and a permeation reinforcement layer is formed by spraying a biochar-based reinforcement slurry onto the hole wall; step S3, five-stage gradient substrate layering: from bottom to top, fill the bottom water quality purification layer, deep slow-release layer, middle main storage layer, middle transition layer and surface permeation layer.The application realizes the integrated operation of efficient rainwater collection, deep purification and precise slow-release water supply through the synergistic cooperation of topographic optimization hole distribution, five-stage gradient substrate, multi-stage water quality purification system and siphon slow-release mechanism.

Description

Technical Field

[0001] This invention relates to the field of landscape greening ecological engineering technology, specifically a method for water storage in landscape greening. Background Technology

[0002] With the rapid advancement of urbanization, urban surfaces are undergoing profound changes. The area of ​​hard paving continues to expand, disrupting the traditional natural hydrological cycle—rainwater cannot effectively infiltrate the ground and is instead quickly drained away through drainage systems, creating urban flooding risks and exacerbating urban water shortages. As a crucial component of the urban ecosystem, green spaces possess both landscape and ecological service functions. Their rainwater absorption, water storage, and evaporation / transpiration capabilities are key aspects of urban sponge city construction. However, current green spaces generally face a dual dilemma of "flooding during the rainy season and drought during the dry season": on the one hand, during heavy rainfall events, the soil infiltration capacity of green spaces is insufficient, and rainwater runoff carries pollutants into urban water bodies; on the other hand, during dry seasons, insufficient water supply to plants necessitates extensive artificial irrigation to maintain the landscape effect, resulting in a huge waste of water resources. Statistics show that urban green space water consumption in my country accounts for approximately 8% to 15% of total urban water consumption, and in some water-scarce cities, it can reach as high as 20%. Therefore, the research and application of water-saving green space technologies have become an urgent need.

[0003] Currently, water storage and conservation technologies in landscaping mainly develop along technical routes such as chemical water-retaining agents, physical water storage structures, soil improvement, and vertical greening water storage. The chemical water-retaining agent route utilizes the super absorbent capacity of polymer water-absorbing resins to store water; the physical water storage structure route stores rainwater runoff through water storage plates and modules; the soil improvement route improves soil water retention capacity by adding organic matter and vermiculite; and the vertical greening water storage route develops specialized substrates and drainage systems for special scenarios such as roof gardens. Although existing technologies have improved the water storage capacity of landscaping to some extent, many technical challenges and shortcomings still exist in practical applications.

[0004] First, the water storage structure is too simple, resulting in low water retention efficiency and poor durability. Existing technologies mostly employ single-dimensional water storage strategies, relying either on chemical water-retaining agents or physical water storage structures, failing to form a multi-layered, multi-functional synergistic water storage system. While chemical water-retaining agents have high initial water absorption rates, their molecular chains are prone to breakage and degradation after repeated water absorption-release-drying cycles in the soil environment. Typically, the water absorption rate decreases by more than 50% after 2-3 years of use, significantly reducing water storage capacity. Physical water storage boards / modules suffer from limited contact surface with the soil, difficulty in root penetration, and an effective water storage space utilization rate of less than 40%. More importantly, a single water storage structure cannot simultaneously meet the full-chain requirements of "rapid infiltration - large-scale storage - slow release - precise water supply," resulting in a persistent contradiction between insufficient water retention during the rainy season and inadequate supply during the dry season.

[0005] Secondly, the lack of consideration for topographical factors significantly limits the efficiency of rainwater collection. Existing water storage methods generally ignore the impact of topographical conditions on rainwater collection and infiltration, employing a uniform, one-size-fits-all design with evenly distributed holes. In reality, the micro-topographical undulations, slope, aspect, and elevation of green areas directly determine the direction and collection patterns of rainwater—rainwater easily flows downhill on slopes, while waterlogging easily accumulates in depressions. The water storage needs and conditions vary significantly across different topographical locations. Uniform designs that do not consider topographical differences result in insufficient water storage at the top of slopes and excessive water storage in depressions, even forming stagnant zones. This significantly reduces overall collection efficiency, making it difficult to exceed 60% of rainwater resource utilization.

[0006] Secondly, the lack of water quality retention capabilities results in unstable rainwater quality and limited utilization. Existing water storage methods generally focus only on the quantity of water accumulated, neglecting the preservation of its quality. During collection and storage, rainwater dissolves or carries atmospheric sediments, road pollutants, leaf humus, and nutrient leaching from the soil, leading to increased levels of suspended solids, organic matter, and nitrogen and phosphorus nutrients in the stored water. Long-term storage can also foster algae and pathogens, producing unpleasant odors. Deteriorating water quality not only affects plant health, but more seriously, stored rainwater cannot be directly used as a source for pesticide dilution or nutrient solution preparation—pest and disease control and foliar fertilization in landscaping typically require clean water, which substandard water storage cannot meet, significantly limiting its utilization and economic value.

[0007] Finally, the construction methods are highly destructive and costly, making widespread application difficult. Traditional water storage systems mostly employ open-cut construction techniques, requiring large-scale excavation of planting areas, destruction of existing vegetation and soil structure, followed by the re-laying of the water storage layer and backfilling. This construction method is not only time-consuming and costly, with renovation costs reaching 200-500 yuan per square meter, but also causes severe damage to plant roots and even plant death in existing green areas. For point- or linear green areas such as urban street trees and green belts, open-cut construction also faces practical obstacles such as complex underground pipelines, significant traffic interference, and limited construction space, resulting in a large number of existing green areas being unable to undergo water storage renovation, and extremely limited coverage of rainwater resource utilization. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a method for water storage in landscaping, which solves the problems of low water retention efficiency of single water storage structures, poor water collection efficiency due to failure to consider topographic factors, lack of water quality maintenance function, and high construction damage and renovation costs.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for water storage in landscaping, comprising the following steps: Step S1, Topographic Survey and Site Optimization Design: Conduct a topographic survey of the target greening area, establish a digital elevation model, and obtain information on slope, aspect, drainage line, and depression topography; differentiate borehole layout according to topographic features: in sloping areas, arrange borehole rows along contour lines, with the borehole spacing gradually increasing from sparse to dense along the slope direction; when the slope is greater than 15°, set up a micro-intercepting ditch above each row of boreholes; in depression areas, densify the borehole layout in the center and around the perimeter, and set up a ring-shaped drainage ditch at the edge; in flat areas, evenly distribute boreholes according to an equilateral triangular grid. Step S2, In-situ Drilling and Hole Wall Permeability Reinforcement: According to the optimized point layout plan, a spiral drilling machine is used to drill vertically downwards. In the tree area, the hole diameter is 10-12cm and the hole depth is 80-100cm, and in the shrub area, the hole diameter is 8-10cm and the hole depth is 60-80cm. During the drilling process, the topsoil, middle soil and deep soil are collected in layers and stored separately. Biochar-based reinforcement slurry is sprayed into the inner wall of the borehole to form a permeable reinforcement layer with a thickness of 0.5-1.5cm. The biochar-based reinforcement slurry is made of 25-35 parts modified biochar, 8-12 parts bentonite, 3-6 parts plant fiber, 0.5-1.5 parts chitosan and 60-80 parts water by weight. After spraying, it is left to stand for 2-4 hours to allow it to initially set. Step S3: Layered Filling of Five-Level Gradient Water Storage and Water Quality Maintenance Matrix: Five types of matrix are filled from bottom to top, forming a five-level gradient structure: bottom water purification layer, deep slow-release layer, middle main storage layer, middle transition layer, and surface seepage layer. Compaction is performed every 10-15cm of filling. The bottom water purification layer, 8-12cm thick, is composed of modified zeolite, volcanic rock, and maifanite mixed in a volume ratio of 3:4:3 to 4:4:2, with a particle size of 0.5-1.5cm and a compaction degree ≤65%. The deep slow-release layer, 15-25cm thick, is composed of deep soil, modified biochar, and water-absorbing resin mixed in a volume ratio of 3:1:0.02 to 5:1:0.01. Backfill with 0.3%–0.8% Bacillus subtilis inoculant, compacted to 80%–85%; the middle main storage layer is 25–35 cm thick, composed of middle soil, modified biochar, vermiculite, and modified zeolite powder in a volume ratio of 4:1:1:0.3–6:2:1:0.5, compacted to 75%–80%; the middle transition layer is 8–12 cm thick, composed of middle soil, coarse sand, and coconut shell activated carbon in a volume ratio of 5:3:1–6:3:1, compacted to 72%–78%; the surface infiltration layer is 10–15 cm thick, composed of surface soil, coarse sand, and coconut coir in a volume ratio of 5:2:1–7:3:1, compacted to 70%–75%. Step S4: Implanting the siphon slow-release and water quality monitoring component: While filling the middle main storage layer, vertically implant the siphon slow-release and water quality monitoring composite pipe along the center of the cavity. The composite pipe includes a main body, surrounding capillary branches, and a built-in water quality monitoring unit. The main body has a diameter of 2-3 cm, and the pipe wall has water-permeable holes and is covered with a non-woven filter membrane. The capillary branches extend horizontally in a radial pattern, with a length of 5-8 cm, and the ends are embedded in the pore wall permeability reinforcement layer for 0.5-1 cm. The water quality monitoring unit integrates a pH sensor, a conductivity sensor, and a dissolved oxygen sensor, and is located from the bottom of the middle main storage layer to the top of the deep slow-release layer. The upper end of the composite pipe extends out of the ground and is equipped with a sealed cap with a water intake interface, and the lower end is equipped with a conical water guide head that inserts into the bottom water purification layer. Step S5: Construct a terrain-adaptive surface water collection and drainage structure: Based on the terrain design, construct a water collection and drainage structure around the top of the hole. On flat terrain, construct a ring-shaped water collection trough. On sloping terrain, construct an arc-shaped water interception embankment on the upslope side and an opening for water diversion on the downslope side. On depression terrain, connect the hole to the water diversion ditch. A water diversion gap is set between the water collection trough and the hole, and a gravel buffer strip is laid on the outside. The top of the hole is covered with a permeable cover plate. Step S6, Initial Rainwater Diversion and Multi-stage Purification: A replaceable initial rainwater filtration module is installed below the permeable cover. From top to bottom, it consists of a coarse filter layer, a fine filter layer, and an antibacterial layer, with a total thickness of 4-6 cm. The first 2-5 mm of rainfall is intercepted by the initial rainwater filtration module. Subsequent rainwater is then purified step by step through the surface infiltration layer, the middle transition layer, the middle main storage layer, the deep slow-release layer, and the bottom water purification layer before being stored. Step S7, System Debugging and Water Quality Calibration Start-up: Inject clean tap water into the upper part of the composite pipe to 60% to 80% of the designed water storage capacity. After standing for 48 hours, take a water sample to test the water quality indicators and ensure that the pH value is 6.5 to 8.0, suspended solids ≤20mg / L, chemical oxygen demand ≤50mg / L, ammonia nitrogen ≤5mg / L, and total phosphorus ≤0.5mg / L. After the water quality meets the standards, the system start-up is completed.

[0010] Preferably, in step S1, the hole spacing in the sloping area gradually changes along the slope direction as follows: the center-to-center distance between adjacent holes is 55-65cm in the upper part of the slope, 45-55cm in the middle part of the slope, and 35-45cm in the lower part of the slope. The micro-intercepting ditch extends along the contour line, with a width of 8-12cm and a depth of 5-8cm, and is filled with gravel with a particle size of 2-4cm. The center-to-center spacing of the holes in the depression area is 30-40cm, and an overflow outlet is set at the lowest point of the depression. The theoretical catchment area for each borehole was calculated based on topographic data. The catchment area is positively correlated with the borehole depth and diameter; for every 0.5m increase in catchment area... 2 The drilling depth increases by 5-10 cm, and the hole diameter increases by 0.5-1 cm.

[0011] Preferably, in step S3, the modified zeolite, volcanic rock, and maifanite in the bottom water purification layer are mixed in a volume ratio of 3.5:4:2.5, with a particle size distribution of 40% for particles of 0.5-1cm and 60% for particles of 1-1.5cm. The volcanic rock surface is pre-treated with biofilm by immersing the volcanic rock in activated sludge mixture and aerating it for 7-10 days to form a biofilm on the volcanic rock surface.

[0012] Preferably, in step S3, the Bacillus subtilis inoculant added to the deep slow-release layer uses porous vermiculite particles as a carrier, with an effective viable bacteria count ≥10. 8 CFU / g; The microbial agent is premixed with modified biochar before the substrate is filled, and the mixing ratio is 1:20 to 1:30. The modified zeolite powder in the middle main reservoir has a particle size of 80-120 mesh and is added at 3%-5% of the total matrix volume. The modified zeolite was prepared by sodium-aluminum salt composite modification, with an ammonia nitrogen adsorption capacity ≥15mg / g and a total phosphorus adsorption capacity ≥2mg / g.

[0013] Preferably, in step S4, the capillary branches are arranged in layers at intervals of 8 to 12 cm along the axial direction of the main body, with 3 to 4 branches in each layer, and the upper and lower layers are staggered at 45° to 60°. The capillary branches are filled with hydrophilic polyester fiber bundles with a fineness of 3–5 denier and a packing density of 0.2–0.3 g / cm³. 3 ; The sensor probe of the water quality monitoring unit contacts the water outside the pipe through a special opening in the pipe wall. The monitoring data is transmitted to an external receiving terminal via Bluetooth Low Energy or LoRa wirelessly. The monitoring frequency is once every 1 to 24 hours.

[0014] Preferably, in step S6, the antibacterial layer of the initial rain filter module is silver-loaded zeolite particles with a silver content of 0.3% to 0.5% and a particle size of 2 to 3 mm. Silver-loaded zeolite is prepared by immersing modified zeolite in silver nitrate solution and then calcining it. Silver ions are released slowly, and the antibacterial effect lasts for 3 to 6 months. The initial rain filter module has a modular structure, a handle, and a replacement cycle of 3 to 6 months.

[0015] Preferably, the modified biochar is prepared by a two-step method of alkali activation and acid modification: Agricultural waste straw is pyrolyzed at 400-500℃ with limited oxygen for 2-3 hours to obtain raw biochar; Activation is performed by soaking in a 1-2 mol / L NaOH solution in a water bath at 60-80℃ for 12-24 hours, with a solid-liquid ratio of 1:8-1:12; After washing with water until neutral, the surface is modified by soaking in a 5%–10% citric acid solution at 40–60°C for 6–12 hours. The resulting modified biochar has a specific surface area ≥350 m². 2 / g, pore volume ≥0.25cm 3 / g, with a saturated water absorption rate of 8 to 12 times its own weight.

[0016] Preferably, in step S2, the chitosan in the biochar-based reinforced slurry is food-grade chitosan with a degree of deacetylation ≥ 85%, which is dissolved in 1% to 2% acetic acid solution before being added to the slurry. The slurry is sprayed in a top-down spiral motion, with a spray pressure of 0.2–0.4 MPa and a travel speed of 5–10 cm / s. The slurry penetrates into the soil of the borehole wall to a depth of 0.3–0.8 cm.

[0017] Preferably, the method further includes water quality maintenance and material regeneration steps: every 6 to 12 months, water is drawn from the storage area through the water intake interface to test the water quality. When the ammonia nitrogen exceeds 8 mg / L or the chemical oxygen demand exceeds 80 mg / L, the zeolite is regenerated by injecting a 1% to 2% NaCl solution through the composite pipe. The amount of regeneration solution is 1 to 2 times the volume of the bottom purification layer. After soaking for 6 to 8 hours, the solution is discharged. At the same time, Bacillus subtilis inoculant is added to maintain microbial activity.

[0018] This invention provides a method for water storage in landscaping. It has the following beneficial effects: This invention, through topographic survey and differentiated borehole design, matches the borehole layout with the natural collection patterns of rainwater. On slopes, boreholes are placed along contour lines in conjunction with intercepting ditches to gradually intercept slope runoff. In depressions, denser borehole placement is combined with diversion ditches to fully utilize natural water collection advantages. This fundamentally solves the problem of the traditional uniform borehole layout being out of sync with topographic conditions, thereby improving the overall rainwater collection efficiency and achieving highly efficient water collection that is adaptive to the terrain.

[0019] This invention utilizes a five-level gradient matrix structure consisting of a bottom water purification layer, a deep slow-release layer, a middle main storage layer, a middle transition layer, and a surface infiltration layer. Combined with a multi-level purification system using modified zeolite, volcanic rock, maifanite, modified biochar, coconut shell activated carbon, and Bacillus subtilis, it forms a three-dimensional water quality assurance mechanism of surface primary filtration and five-layer purification. This significantly reduces suspended solids, chemical oxygen demand, ammonia nitrogen, total phosphorus, and other indicators in the stored rainwater, ensuring that the effluent quality consistently meets the standards for landscaping irrigation. It also satisfies the clean water source requirements for pesticide dilution and nutrient solution preparation, greatly expanding the utilization pathways and economic value of stored water.

[0020] This invention utilizes a composite pipe design combining siphon slow release and water quality monitoring to achieve adaptive slow release water supply driven by capillary action and matrix potential gradient. During drought periods, the continuous water supply can reach 28-35 days, improving water storage utilization. It also integrates online monitoring functions for pH, conductivity, and dissolved oxygen, and with the top water intake interface, it enables convenient access to stored water and real-time water quality monitoring, solving the problems of traditional water storage systems that prioritize storage over utilization and have weak water supply regulation capabilities.

[0021] This invention utilizes an in-situ drilling construction process and employs a spiral drilling machine for micro-operation, resulting in a construction area damage rate of only about 3%, which is far lower than the efficiency of traditional open-cut construction. It can be directly applied to the water storage renovation of existing green areas without the need for large-scale excavation and vegetation destruction, thus reducing construction costs, shortening the construction cycle, and significantly improving the scalability and economy of the technology. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the overall steps of the present invention; Figure 2 This is a schematic diagram of the five-stage gradient water storage and water quality maintenance of the present invention; Figure 3 These are schematic diagrams illustrating different terrain-specific hole layout methods of the present invention; Figure 4 This is a schematic diagram of the multi-stage water purification path of the present invention; Figure 5 This is a comparison chart of the water storage performance of the present invention; Figure 6 This is a comparison chart of the effluent water quality of the present invention. Detailed Implementation

[0023] 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.

[0024] Example: like Figure 1-6As shown, this embodiment of the invention provides a method for water storage in landscaping, including the following steps: Step S1, Topographic survey and site optimization design: Conduct topographic survey of the target greening area, establish a digital elevation model, and differentiate the layout of boreholes based on topographic features such as slope, aspect, catchment line, and depressions; Step S2, In-situ drilling and borehole wall permeability reinforcement: Drill vertically using a spiral drilling machine according to the optimized sites, and spray biochar-based reinforcement slurry into the borehole wall to form a permeable reinforcement layer; Step S3, Layered filling of a five-level gradient water storage and water quality maintenance matrix: Fill the matrix from bottom to top... Step S4: Fill the bottom water purification layer, deep slow-release layer, middle main storage layer, middle transition layer, and surface infiltration layer; Step S5: Install siphon slow-release and water quality monitoring components: Install the siphon slow-release and water quality monitoring composite pipe along the center of the hole; Step S6: Construct a terrain-adaptive surface water collection and drainage structure: Construct a corresponding water collection structure according to the terrain; Step S7: Initial rainwater diversion and multi-stage purification treatment: Set up an initial rainwater filtration module, and store the rainwater after multi-stage purification; Step S8: System debugging and water quality calibration start-up: After water injection debugging and calibration to meet the water quality standards, the system is started up.

[0025] Example 1:

[0026] This experiment was conducted on a gentle slope roadside greenbelt along a main road in a city. The slope was approximately 8°. The tree species used were camphor trees, 8 years old, with a diameter at breast height (DBH) of approximately 15 cm. The planting spacing was 5 meters. The soil type was yellow-brown soil with a bulk density of 1.35 g / cm³. 3 The initial field capacity was 28.6%. The specific steps are as follows: Step S1: Topographic Survey and Site Optimization Design: RTK surveying equipment was used to collect regional topographic data and establish a digital elevation model. The area is a gentle slope with an 8° gradient and a slope length of approximately 30m. Drill rows were arranged along contour lines, with 6 boreholes per row (one per tree). At the top of the slope (top 1 / 3), the borehole spacing was 60cm, the diameter was 9cm, and the depth was 85cm; at the middle of the slope (middle 1 / 3), the spacing was 50cm, the diameter was 10cm, and the depth was 90cm; at the bottom of the slope (bottom 1 / 3), the spacing was 40cm, the diameter was 11cm, and the depth was 95cm. The 6 boreholes around each tree were arranged in a regular hexagonal pattern, 1.2m from the trunk. Because the slope was less than 15°, no micro-drainage ditches were constructed.

[0027] Step S2, In-situ Drilling and Hole Wall Permeability Reinforcement: A small spiral drilling machine is used to drill vertically at the designed locations. During drilling, undisturbed soil is collected in layers: topsoil (0-20cm), middle soil (20-60cm), and deep soil (below 60cm) are stored in separate containers. After drilling, the hole walls and bottom are flushed with 0.25MPa compressed air. Prepare the biochar-based reinforcement slurry: Take 30 parts by weight of modified biochar, 10 parts of bentonite, 5 parts of rice husk fiber (2-4mm in length), 1 part of chitosan (90% deacetylation), and 70 parts of water. The chitosan is dissolved in a 1.5% acetic acid solution beforehand and then added. The slurry is sprayed using a top-down spiral motion at a pressure of 0.3MPa and a speed of 8cm / s, forming a permeable reinforcement layer approximately 1.0cm thick, with a penetration depth of approximately 0.5cm. Allow the slurry to stand for 3 hours to allow initial setting.

[0028] Step S3: Layered Filling of the Five-Level Gradient Water Storage and Water Quality Maintenance Substrate: Fill in layers from bottom to top, compacting every 12cm thickness at a pressure of 0.1MPa for 15 seconds. Bottom Water Purification Layer (10cm): Modified zeolite, volcanic rock, and maifanite are mixed in a volume ratio of 3.5:4:2.5, with a particle size distribution of 40% (0.5-1cm) and 60% (1-1.5cm). The volcanic rock is pre-cultured with activated sludge for 8 days, with a compaction degree of 60%. Deep Slow-Release Layer (20cm): Deep soil, modified biochar, and absorbent resin are mixed in a volume ratio of 4:1:0.015, with the addition of 0.5% Bacillus subtilis inoculant (effective viable count 2.5 × 10⁻⁶). 8 CFU / g (vermiculite carrier), microbial agent and modified biochar are premixed at a ratio of 1:25, with a compaction degree of 83%. Middle main storage layer (30cm): Middle soil, modified biochar, vermiculite, and modified zeolite powder (100 mesh) are mixed at a volume ratio of 5:1.5:1:0.4, with a compaction degree of 78%. Middle transition layer (10cm): Middle soil, coarse sand, and coconut shell activated carbon are mixed at a volume ratio of 5.5:3:1, with a compaction degree of 75%. Top layer infiltration layer (12cm): Top soil, coarse sand, and coconut coir are mixed at a volume ratio of 6:2.5:1, with a compaction degree of 72%.

[0029] Step S4: Implantation of the siphon-release and water quality monitoring component: Simultaneously with filling the middle main storage layer, a composite tube is vertically implanted along the center of the pores. The main tube has a diameter of 2.5 cm and a permeable pore diameter of 0.4 cm, covered with a 250-mesh non-woven filter membrane. Three capillary branches are arranged in each layer, with a layer spacing of 10 cm, for a total of three layers, staggered at 60°. The branch tubes are 6 cm long and embedded 0.8 cm into the pore wall. The branch tubes are filled with hydrophilic polyester fiber bundles (4 denier, 0.25 g / cm³). 3The lower conical water guide head has a 35° cone angle and inserts 4cm into the bottom purification layer, featuring three spiral water guide channels. The water quality monitoring unit integrates a pH, conductivity, and dissolved oxygen sensor, located at the bottom of the middle main reservoir, and uses LoRa wireless transmission, monitoring every 6 hours. The upper end extends 2.5cm above the ground surface, equipped with a sealing cap and a Luer water intake interface.

[0030] Step S5: Construct a terrain-adaptive surface water collection and drainage structure: For gentle slopes, an upslope curved intercepting embankment (4cm high, 20cm radius) is used in conjunction with an opening (15cm wide) on the downslope side. Two water-guiding slots, 1.0cm wide, are provided and filled with 0.5-1cm fine gravel. The gravel buffer zone is 10cm wide with a particle size of 1.5cm. The permeable cover has a 25% opening rate, is made of plant fiber composite material, and is flush with the ground surface.

[0031] Step S6, Initial Rainwater Diversion and Multi-Stage Purification: An initial rainwater filtration module with a total thickness of 5cm is installed below the permeable cover. The upper coarse filter layer consists of 2cm of quartz sand (2-4mm), the middle fine filter layer consists of 2cm of activated carbon fiber felt, and the lower antibacterial layer consists of 1cm of silver-loaded zeolite (2-3mm, silver content 0.42%). The modular design includes a handle and is designed to divert 3mm of rainfall. After entering the pores, rainwater sequentially passes through a surface infiltration layer for physical filtration, a middle transition layer for activated carbon adsorption, a middle main storage layer for combined biochar-zeolite adsorption, a deep slow-release layer for microbial degradation, and a bottom water purification layer for deep purification.

[0032] Step S7: System Debugging and Water Quality Calibration Start-up: Slowly inject clean tap water through the water inlet, 4.0L per hole (approximately 70% of the design capacity), at an injection rate of 0.8L / min. After standing for 48 hours, take a water sample for testing. Test results: pH 7.2, suspended solids 12.5mg / L, chemical oxygen demand 38.6mg / L, ammonia nitrogen 3.2mg / L, total phosphorus 0.32mg / L, fecal coliforms 680 CFU / L. Moisture content of each layer: bottom purification layer saturated, deep layer 39.1%, middle layer 49.5%, surface layer 29.3%. All water quality meets the standards, and the system startup is complete.

[0033] Preparation of modified biochar: Corn stalks were used as raw material and crushed to approximately 1 cm. The mixture was pyrolyzed under nitrogen protection at a rate of 8℃ / min to 450℃ for 2.5 hours. Activation was then performed in a 70℃ water bath with a 1.5 mol / L NaOH solution at a solid-liquid ratio of 1:10 for 18 hours. After washing to neutrality, the biochar was modified with an 8% citric acid solution at 50℃ for 9 hours at a solid-liquid ratio of 1:8. After washing and drying, the biochar was sieved to a mesh size of 30. The specific surface area was measured to be 386 m². 2 / g, pore volume 0.28cm 3 / g, saturated water absorption rate 10.2 times.

[0034] Preparation of modified zeolite: Natural clinoptilolite (20-40 mesh) was used as raw material. It was sodium-modified in a 1.5 mol / L NaCl solution at 70℃ for 5 hours (solid-liquid ratio 1:9). Then, it was modified with 4% aluminum sulfate solution at room temperature for 10 hours (solid-liquid ratio 1:7). Finally, it was calcined at 350℃ for 2 hours. The ammonia nitrogen adsorption capacity was measured to be 16.8 mg / g, and the total phosphorus adsorption capacity was 2.3 mg / g.

[0035] Test results: After the system stabilized, the rainwater harvesting efficiency reached 89.3%, and the water storage capacity per unit area was 56.2 L / m². 2 During the drought, water was supplied continuously for 32 days, with a water storage utilization rate of 78.5% and a construction area damage rate of 3.1%. The effluent quality consistently met the requirements of the "Standards for Irrigation Water Quality" (GB5084) and can be directly used for pesticide dilution and foliar fertilizer formulation. After 3 years, the water storage retention rate was 89.2%, and the soil microbial diversity index was 3.92.

[0036] Example 2:

[0037] This embodiment is basically the same as Embodiment 1, except that the process parameters are taken as the lower limit of the scope of the claims, as detailed below: The slope is 6°. The hole spacing gradually changes from 55cm at the top of the slope to 45cm in the middle and 35cm at the bottom. The hole diameter is 9cm and the hole depth is 80cm. The biochar-based reinforcement slurry consists of 25 parts modified biochar, 8 parts bentonite, 3 parts plant fiber, 0.5 parts chitosan, and 60 parts water. The reinforcement layer thickness is 0.5cm, the injection pressure is 0.2MPa, and it is allowed to stand for 2 hours. The bottom water purification layer is 8cm thick, with a modified zeolite:volcanic rock:maifanite ratio of 3:4:3 and a compaction degree of 65%. The deep slow-release layer is 15cm thick, with a volume ratio of 3:1:0.02, a bacterial agent dosage of 0.3%, and a compaction degree of 80%. The middle main storage layer is 25cm thick, with a volume ratio of 4:1:1:0.3 and a compaction degree of 75%. The middle transition layer is 8cm thick, with a volume ratio of 5:3:1 and a compaction degree of 72%. The surface infiltration layer is 10cm thick, with a volume ratio of 5:2:1 and a compaction degree of 70%. The main composite pipe has a diameter of 2cm, with 3 capillary branches per layer, 8cm spacing between layers, for a total of 2 layers. The branch pipes are 5cm long and embedded 0.5cm. The initial rain filter module has a total thickness of 4cm and a designed discharge flow rate of 2mm. Modified biochar: pyrolyzed at 400℃ for 2 hours, activated with 1mol / L NaOH for 12 hours, and modified with 5% citric acid for 6 hours, resulting in a specific surface area of ​​350m². 2 / g, saturated water absorption rate 8 times.

[0038] Test results: Rainwater harvesting efficiency 82.5%, water storage capacity per unit area 45.8 L / m² 2During the drought, water was supplied continuously for 26 days, with a water storage utilization rate of 72.3% and a construction area damage rate of 3.5%. The effluent pH was 7.0, suspended solids were 16.8 mg / L, chemical oxygen demand was 46.5 mg / L, ammonia nitrogen was 4.5 mg / L, and total phosphorus was 0.45 mg / L. The 3-year water storage retention rate was 85.6%.

[0039] Example 3:

[0040] This embodiment is basically the same as Embodiment 1, except that the process parameters are taken as the upper limit of the scope of the claims, as detailed below: The slope is 12°, with the hole spacing gradually changing from 65cm at the top, 55cm in the middle, and 45cm at the bottom. The hole diameter is 12cm and the hole depth is 100cm. Due to the slope approaching 15°, a micro-intercepting ditch is added, 12cm wide and 8cm deep, filled with 3cm gravel. The biochar-based reinforcement slurry consists of 35 parts modified biochar, 12 parts bentonite, 6 parts plant fiber, 1.5 parts chitosan, and 80 parts water, with a reinforcement layer thickness of 1.5cm, a spraying pressure of 0.4MPa, and a settling time of 4 hours. The bottom water purification layer is 12cm thick, composed of modified zeolite:volcanic rock:maifanite in a 4:4:2 ratio, with a compaction degree of 65%. The deep slow-release layer is 25cm thick, with a volume ratio of 5:1:0.01, a bacterial agent dosage of 0.8%, and a compaction degree of 85%. The middle main storage layer is 35cm thick, with a volume ratio of 6:2:1:0.5 and a compaction degree of 80%. The middle transition layer is 12cm thick, with a volume ratio of 6:3:1 and a compaction degree of 78%. The surface infiltration layer is 15cm thick, with a volume ratio of 7:3:1 and a compaction degree of 75%. The main composite pipe has a diameter of 3cm, with 4 capillary branches per layer, 12cm spacing between layers, for a total of 4 layers. The branch pipes are 8cm long and embedded 1.0cm. The initial rainwater filtration module has a total thickness of 6cm and a designed discharge flow rate of 5mm. Modified biochar: pyrolyzed at 500℃ for 3 hours, activated with 2mol / L NaOH for 24 hours, and modified with 10% citric acid for 12 hours, resulting in a specific surface area of ​​420m². 2 / g, saturated water absorption rate 12 times.

[0041] Test results: Rainwater harvesting efficiency 93.8%, water storage capacity per unit area 68.5 L / m² 2 During the drought, water was supplied continuously for 38 days, with a water storage utilization rate of 82.1% and a construction area damage rate of 2.8%. The effluent pH was 7.4, suspended solids were 9.2 mg / L, chemical oxygen demand was 32.4 mg / L, ammonia nitrogen was 2.5 mg / L, and total phosphorus was 0.25 mg / L. The 3-year water storage retention rate was 91.5%.

[0042] Example 4:

[0043] This embodiment is basically the same as Embodiment 1, except that the terrain-optimized perforation technology is not used. Instead, a uniform perforation method is adopted throughout the entire area (uniform perforation spacing of 50cm, uniform perforation diameter of 10cm, and uniform perforation depth of 90cm). The other technical solutions, such as the five-level gradient matrix, water purification system, and siphon slow-release device, are completely retained to verify the independent contribution of the terrain optimization technology.

[0044] Test results: Rainwater harvesting efficiency 73.8%, water storage capacity per unit area 43.5 L / m² 2 During the drought period, water was supplied continuously for 26 days, with a water storage utilization rate of 74.6%. The effluent quality was basically the same as in Example 1, with a pH of 7.5, suspended solids of 22.6 mg / L, chemical oxygen demand of 68.5 mg / L, ammonia nitrogen of 7.6 mg / L, and total phosphorus of 0.85 mg / L. Compared with Example 1, it can be seen that the terrain optimization technology improved the water collection and storage efficiency by about 15.5 percentage points, making a significant contribution to the overall water storage effect.

[0045] Comparative Example 1: This comparative example uses traditional landscaping water retention methods, namely soil mixed with water-retaining agents and conventional irrigation, without utilizing the terrain optimization, five-level gradient substrate, water purification system, and siphon slow-release device of this invention. Specifically, in a tree-lined area with identical conditions, the soil is tilled to a depth of 30cm, and 0.5% of ordinary polyacrylamide water-retaining agent (with a water absorption ratio of approximately 300 times) is evenly added. After leveling, the original vegetation is restored. No layered structure, water collection system, purification facilities, or water supply device are included.

[0046] Test results: Water storage capacity per unit area: 18.2 L / m² 2 The rainwater storage efficiency is 35.2%, continuous water supply for 10 days during drought, water utilization rate is 38.5%, construction area damage rate is 85.0%, water retention rate after 3 years is 32.6%, and soil microbial diversity index is 2.95. Compared with Example 1, the present invention has orders of magnitude improvement in water storage capacity, collection efficiency, continuous water supply days, water utilization rate, and construction damage, and the effluent quality meets the standards for irrigation and pesticide dilution, while the traditional method has no water purification function.

[0047] Comparative Example 2: This comparative example is essentially the same as Example 1, except that it does not use a five-level gradient matrix and a multi-level water purification system, but instead employs a single water storage layer structure. Specifically, the entire borehole is backfilled with homogeneous soil mixed with 10% modified biochar, without a bottom water purification layer, a middle transition layer, or any purification materials such as zeolite, volcanic rock, maifanite, activated carbon, or Bacillus subtilis. The terrain-optimized pore layout and siphon slow-release device are retained.

[0048] Test results: Rainwater harvesting efficiency was 87.5%, similar to Example 1. However, the effluent quality significantly declined: suspended solids 35.6 mg / L, chemical oxygen demand 95.8 mg / L, ammonia nitrogen 12.3 mg / L, total phosphorus 1.25 mg / L, and fecal coliforms 5800 CFU / L. The effluent quality could not meet the requirements for pesticide dilution and nutrient solution ratio, and could only be used for extensive irrigation. Compared with Example 1, it is evident that the five-stage gradient substrate and multi-stage purification system are the core to ensuring effluent quality; after removal, the water quality indicators deteriorated by 2-3 times.

[0049] Comparative Example 3: This comparative example is essentially the same as Example 1, except that it does not use a siphon-based slow-release and water quality monitoring composite pipe, but instead employs gravity-based natural seepage for water supply. Specifically, no composite pipe is implanted inside the pores; water is transported naturally solely by gravity and soil capillary action. The terrain optimization, five-level gradient matrix, and water purification system are retained.

[0050] Test results: Rainwater harvesting efficiency was 88.6%, and the effluent quality was basically the same as in Example 1. However, continuous water supply during the drought period lasted only 18 days, with a water storage utilization rate of 52.3%, significantly lower than the 32 days and 78.5% in Example 1. Compared with Example 1, it can be seen that the siphon slow-release device significantly extended the water supply cycle through an active capillary water transport mechanism, increasing the water storage utilization rate by 26 percentage points, which is a key technology for achieving precise slow-release water supply.

[0051] Performance Comparison Table of Each Embodiment and Comparative Example

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for water storage in landscaping, characterized in that, Includes the following steps: Step S1, Topographic Survey and Site Optimization Design: Conduct a topographic survey of the target greening area, establish a digital elevation model, and obtain information on slope, aspect, drainage line, and depression topography; differentiate borehole layout according to topographic features: in sloping areas, arrange borehole rows along contour lines, with the borehole spacing gradually increasing from sparse to dense along the slope direction; when the slope is greater than 15°, set up a micro-intercepting ditch above each row of boreholes; in depression areas, densify the borehole layout in the center and around the perimeter, and set up a ring-shaped drainage ditch at the edge; in flat areas, evenly distribute boreholes according to an equilateral triangular grid. Step S2, In-situ Drilling and Hole Wall Permeability Reinforcement: According to the optimized point layout plan, a spiral drilling machine is used to drill vertically downwards. In the tree area, the hole diameter is 10-12cm and the hole depth is 80-100cm, and in the shrub area, the hole diameter is 8-10cm and the hole depth is 60-80cm. During the drilling process, the topsoil, middle soil and deep soil are collected in layers and stored separately. Biochar-based reinforcement slurry is sprayed into the inner wall of the borehole to form a permeable reinforcement layer with a thickness of 0.5-1.5cm. The biochar-based reinforcement slurry is made of 25-35 parts modified biochar, 8-12 parts bentonite, 3-6 parts plant fiber, 0.5-1.5 parts chitosan and 60-80 parts water by weight. After spraying, it is left to stand for 2-4 hours to allow it to initially set. Step S3: Layered Filling of Five-Level Gradient Water Storage and Water Quality Maintenance Matrix: Five types of matrix are filled from bottom to top, forming a five-level gradient structure: bottom water purification layer, deep slow-release layer, middle main storage layer, middle transition layer, and surface seepage layer. Compaction is performed every 10-15cm of filling. The bottom water purification layer, 8-12cm thick, is composed of modified zeolite, volcanic rock, and maifanite mixed in a volume ratio of 3:4:3 to 4:4:2, with a particle size of 0.5-1.5cm and a compaction degree ≤65%. The deep slow-release layer, 15-25cm thick, is composed of deep soil, modified biochar, and water-absorbing resin mixed in a volume ratio of 3:1:0.02 to 5:1:0.

01. Backfill with 0.3%–0.8% Bacillus subtilis inoculant, compacted to 80%–85%; the middle main storage layer is 25–35 cm thick, composed of middle soil, modified biochar, vermiculite, and modified zeolite powder in a volume ratio of 4:1:1:0.3–6:2:1:0.5, compacted to 75%–80%; the middle transition layer is 8–12 cm thick, composed of middle soil, coarse sand, and coconut shell activated carbon in a volume ratio of 5:3:1–6:3:1, compacted to 72%–78%; the surface infiltration layer is 10–15 cm thick, composed of surface soil, coarse sand, and coconut coir in a volume ratio of 5:2:1–7:3:1, compacted to 70%–75%. Step S4: Implanting the siphon slow-release and water quality monitoring component: While filling the middle main storage layer, vertically implant the siphon slow-release and water quality monitoring composite pipe along the center of the cavity. The composite pipe includes a main body, surrounding capillary branches, and a built-in water quality monitoring unit. The main body has a diameter of 2-3 cm, and the pipe wall has water-permeable holes and is covered with a non-woven filter membrane. The capillary branches extend horizontally in a radial pattern, with a length of 5-8 cm, and the ends are embedded in the pore wall permeability reinforcement layer for 0.5-1 cm. The water quality monitoring unit integrates a pH sensor, a conductivity sensor, and a dissolved oxygen sensor, and is located from the bottom of the middle main storage layer to the top of the deep slow-release layer. The upper end of the composite pipe extends out of the ground and is equipped with a sealed cap with a water intake interface, and the lower end is equipped with a conical water guide head that inserts into the bottom water purification layer. Step S5: Construct a terrain-adaptive surface water collection and drainage structure: Based on the terrain design, construct a water collection and drainage structure around the top of the hole. On flat terrain, construct a ring-shaped water collection trough. On sloping terrain, construct an arc-shaped water interception embankment on the upslope side and an opening for water diversion on the downslope side. On depression terrain, connect the hole to the water diversion ditch. A water diversion gap is set between the water collection trough and the hole, and a gravel buffer strip is laid on the outside. The top of the hole is covered with a permeable cover plate. Step S6, Initial Rainwater Diversion and Multi-stage Purification: A replaceable initial rainwater filtration module is installed below the permeable cover. From top to bottom, it consists of a coarse filter layer, a fine filter layer, and an antibacterial layer, with a total thickness of 4-6 cm. The first 2-5 mm of rainfall is intercepted by the initial rainwater filtration module. Subsequent rainwater is then purified step by step through the surface infiltration layer, the middle transition layer, the middle main storage layer, the deep slow-release layer, and the bottom water purification layer before being stored. Step S7, System Debugging and Water Quality Calibration Start-up: Inject clean tap water into the upper part of the composite pipe to 60% to 80% of the designed water storage capacity. After standing for 48 hours, take a water sample to test the water quality indicators and ensure that the pH value is 6.5 to 8.0, suspended solids ≤20mg / L, chemical oxygen demand ≤50mg / L, ammonia nitrogen ≤5mg / L, and total phosphorus ≤0.5mg / L. After the water quality meets the standards, the system start-up is completed.

2. The method for water storage in landscaping according to claim 1, characterized in that: In step S1, the hole spacing in the sloping area gradually changes along the slope direction as follows: the center-to-center distance between adjacent holes is 55-65cm in the upper part of the slope, 45-55cm in the middle part of the slope, and 35-45cm in the lower part of the slope. The micro-intercepting ditch extends along the contour line, with a width of 8-12cm and a depth of 5-8cm, and is filled with gravel with a particle size of 2-4cm. The center-to-center spacing of the holes in the depression area is 30-40cm, and an overflow outlet is set at the lowest point of the depression. The theoretical catchment area for each borehole was calculated based on topographic data. The catchment area is positively correlated with the borehole depth and diameter; for every 0.5m increase in catchment area... 2 The drilling depth increases by 5-10 cm, and the hole diameter increases by 0.5-1 cm.

3. The method for water storage in landscaping according to claim 1, characterized in that: In step S3, the modified zeolite, volcanic rock, and maifanite in the bottom water purification layer are mixed in a volume ratio of 3.5:4:2.5, with a particle size distribution of 40% for particles of 0.5-1cm and 60% for particles of 1-1.5cm. The volcanic rock surface is pre-treated with biofilm by immersing the volcanic rock in activated sludge mixture and aerating it for 7-10 days to form a biofilm on the volcanic rock surface.

4. A method for water storage in landscaping according to claim 1, characterized in that: In step S3, the Bacillus subtilis inoculant added to the deep slow-release layer uses porous vermiculite particles as a carrier, with an effective viable count ≥10. 8 CFU / g; The microbial agent is premixed with modified biochar before the substrate is filled, and the mixing ratio is 1:20 to 1:

30. The modified zeolite powder in the middle main reservoir has a particle size of 80-120 mesh and is added at 3%-5% of the total matrix volume. The modified zeolite was prepared by sodium-aluminum salt composite modification, with an ammonia nitrogen adsorption capacity ≥15mg / g and a total phosphorus adsorption capacity ≥2mg / g.

5. A method for water storage in landscaping according to claim 1, characterized in that: In step S4, the capillary branches are arranged in layers along the axial direction of the main body at a spacing of 8-12cm, with 3-4 branches in each layer, and the upper and lower layers are staggered at 45°-60°. The capillary branches are filled with hydrophilic polyester fiber bundles with a fineness of 3–5 denier and a packing density of 0.2–0.3 g / cm³. 3 ; The sensor probe of the water quality monitoring unit contacts the water outside the pipe through a special opening in the pipe wall. The monitoring data is transmitted to an external receiving terminal via Bluetooth Low Energy or LoRa wirelessly. The monitoring frequency is once every 1 to 24 hours.

6. A method for water storage in landscaping according to claim 1, characterized in that: In step S6, the antibacterial layer of the Chuyu filtration module is silver-loaded zeolite particles with a silver content of 0.3% to 0.5% and a particle size of 2 to 3 mm. Silver-loaded zeolite is prepared by immersing modified zeolite in silver nitrate solution and then calcining it. Silver ions are released slowly, and the antibacterial effect lasts for 3 to 6 months. The initial rain filter module has a modular structure, a handle, and a replacement cycle of 3 to 6 months.

7. A method for water storage in landscaping according to claim 1, characterized in that: The modified biochar was prepared via a two-step method of alkali activation followed by acid modification. Agricultural waste straw is pyrolyzed at 400-500℃ with limited oxygen for 2-3 hours to obtain raw biochar; Activation is performed by soaking in a 1-2 mol / L NaOH solution in a water bath at 60-80℃ for 12-24 hours, with a solid-liquid ratio of 1:8-1:12; After washing with water until neutral, the surface is modified by soaking in a 5%–10% citric acid solution at 40–60°C for 6–12 hours. The resulting modified biochar has a specific surface area ≥350 m². 2 / g, pore volume ≥0.25cm 3 / g, with a saturated water absorption rate of 8 to 12 times its own weight.

8. A method for water storage in landscaping according to claim 1, characterized in that: In step S2, the chitosan in the biochar-based reinforced slurry is food-grade chitosan with a degree of deacetylation ≥85%, which is dissolved in 1% to 2% acetic acid solution before being added to the slurry. The slurry is sprayed in a top-down spiral motion, with a spray pressure of 0.2–0.4 MPa and a travel speed of 5–10 cm / s. The slurry penetrates into the soil of the borehole wall to a depth of 0.3–0.8 cm.

9. A method for water storage in landscaping according to claim 1, characterized in that: The method also includes water quality maintenance and material regeneration steps: every 6 to 12 months, water is drawn from the storage area through the water intake interface to test the water quality. When the ammonia nitrogen exceeds 8 mg / L or the chemical oxygen demand exceeds 80 mg / L, the zeolite is regenerated by injecting a 1% to 2% NaCl solution through the composite pipe. The amount of regeneration solution is 1 to 2 times the volume of the bottom purification layer. After soaking for 6 to 8 hours, the solution is discharged. At the same time, Bacillus subtilis inoculant is added to maintain microbial activity.

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