1 general rules

1. 1 The planning and layout of small-scale water storage and diversion projects at roadside and ditch bottom should be included in the comprehensive management plan of small watershed, combined with the management of cultivated land, wasteland and gully in the watershed.

1.2 In arid and semi-arid soil erosion areas, small-scale water storage and diversion projects at roadside and ditch bottom are used as the main water sources to solve drinking water for people and livestock and drought-resistant point irrigation, and puddles, waterlogging pools and springs are planned and utilized in a unified way and implemented in a coordinated manner.

1.3 In the implementation planning, a small watershed should be taken as a unit to comprehensively investigate the road network and the operation law of surface runoff collection in the watershed. According to the observation data of soil and water conservation experimental station, the runoff modulus and soil erosion modulus of various roads (including multi-year average and the value in the next rainstorm with design frequency) are determined respectively as the basic data for the planning and design of puddles and waterlogging pools.

1.4 The distribution of spring water between residential areas and hills in small watersheds (including the location and quantity of spring water in slopes and ditches) should be comprehensively investigated as the basis for the planning and design of spring water utilization between hills.

1.5 The layout of the three measures of water cellar, waterlogging pool and spring water utilization between hills should meet the needs of drinking water for people and livestock and drought-resistant point irrigation, and at the same time give full play to their role in reducing soil erosion. In particular, it is a key task to control water falling into ditches and reduce gully erosion by storing water in waterlogged ponds.

1.6 The design standard of various small-scale storage projects along the highway and at the bottom of the ditch is1~ once every 20 years, and the maximum rainfall is 3 ~ 6h.

1.7 related supporting projects shall meet the following requirements:

1.7. 1, as the source of catchment, should be a fish back with high middle and low sides. Surface runoff should be introduced into the waterlogging pool or water kiln by the drainage ditches on both sides of the road surface, and it is not allowed to meet in the middle of the road surface.

1.7.2 In arid and semi-arid areas, concrete or concrete catchment fields can be laid on roofs, kiln roofs, yards and confluence roads to increase rainfall collection.

2 water cellars

2. 1 puddle planning

2. 1. 1 location of water cellar. Generally, it is arranged beside the village, on the roadside, and where the surface runoff source is sufficient. The pit site should have a deep and solid soil layer, more than 20m away from the ditch head and ditch edge, and more than 0m away from the big tree root/kloc-0. Water cellars in rocky mountainous areas should be built on impervious bedrock.

2. 1.2 Water cellar type and single kiln capacity

2. 1.2.65438+

2. 1.2.2 Kiln-type water cellars can be built where there are cliffs with solid soil on the roadside and large water storage capacity is required, and the volume of a single water cellars is above1100m3.

2. 1.3 number of puddles

2. 1.3. 1 The number of water cellars to be repaired in the planning area should be calculated according to the population, annual per capita water demand and total water demand, deducting the water supply from other water sources (such as spring water utilization between hills), and taking the local representative single cellar capacity.

2. 1.3.2 In areas with large annual rainfall changes, appropriately increase the number of water cellars.

2.2 Water cellar design

2.2. 1 Design of well-type water cellar (Figure 5-3)

Figure 5-3 Schematic Diagram of Well Pit Profile

2.2. 1. 1 The cellar body consists of a cellar barrel, a dry cellar and a water cellar, and the dimensions of each part are as follows:

2.2. 1. 1. 1 Pit bucket (to take water from the ground pit): 0.6~0.7m in diameter and 0.5 ~ 2m in depth.

2.2. 1. 1.2 dry cellar (non-water storage part): the upper part is connected with the cellar barrel, with a depth of 2 ~ 3m. The diameter gradually increases downward, and the diameter of the dispersion is 3 ~ 4m.

2.2. 1. 1.3 water cellar (water storage part): the depth is 3 ~ 5m, and the diameter gradually decreases from the dispersion to the bottom, and the diameter is 2 ~ 3m.

2.2. 1.2 The ground building consists of a pit, a grit chamber and a water inlet pipe, and the dimensions of each part are as follows:

2.2. 1.2. 1 pithead: 0.6~0.7m in diameter, made of brick or stone, 0.3~0.5m higher than the ground.

2.2. 1.2.2 sedimentary sandy land: located at the roadside in the direction of incoming water, 4 ~ 6m away from the pit mouth. The tank is rectangular, with a length of 2 ~ 3m, a width of 1 ~ 2m and a depth of 1.0 ~ 1~2m. The peripheral gradient ratio is1:1.

2.2. 1.2.3 water inlet pipe: circular, with a diameter of 0.2 ~ 0.3m, and connected to the dry cellar at a depth of about 2/3 from the surface of the grit chamber with a slope of1:1.

2.2.2 Design of kiln-type water cellar (Figure 5-4)

Fig. 5-4 schematic cross section of kiln water cellar

2.2.2. 1 The cellar body consists of a water kiln, a kiln roof and a kiln door, and the dimensions of each part are as follows:

2.2.2. 1. 1 water kiln (water storage part): 3-4m deep, 8- 10m long, trapezoidal section, 3-4m wide upper part, and 8: 1 slope ratio on both sides.

2.2.2. 1.2 kiln top (non-water storage part): the length is consistent with that of the water kiln, with a semicircular arch section and a diameter of 3-4m, which is consistent with the width of the upper part of the water kiln (some kiln-type water cellars leave a circular water inlet in the middle of the kiln top, with a diameter of 0.6~0.7m, and the depth varies with the height of the cliff, passing through the ground water inlet from the kiln top).

2.2.2. 1.3 kiln door: the lower section is trapezoidal, the size is the same as that of the water kiln, it is mortar masonry, the thickness is 0.6~0.8m, and it is airtight. Bury a water pipe about 0.5m from the ground and install a faucet, which can drain freely. The cross section of the upper part is semi-circular, the same size as the kiln top, and made of wood (or other materials). There is a small door that can be opened and closed at 1.0m× 1.5m in the middle of the board.

The ground part of 2.2.2.2 consists of three parts: water intake, grit chamber and water inlet pipe. Reference can be made to the design of well-type water kiln, and the size of grit chamber should be appropriately enlarged according to the inflow.

2.3 Water cellar construction

2.3. 1 foundation pit excavation

2.3. 1. 1 well type water cellar excavation. Starting from the pithead, dig vertically downward according to the design size of each department, hang a center line at the pithead, and check the diameter every time the depth is1m.

2.3. 1.2 kiln-type water cellar excavation. Starting from the kiln door, brush the kiln surface first, dig standard sections according to the design size, and dig in step by step until the design length is reached. Hang a center line at the top of the kiln door, make a semi-circular wooden frame with standard size, dig 1m in each direction, and check the section size once.

2.3. 1.3 For water cellars and water kilns that need cement seepage control, after the pit excavation is completed, the cement-nailed yard should also be excavated. The yard eyes are distributed in a pin shape on the cellar wall, with a distance of about 20cm from top to bottom, a diameter of 5 ~ 8 cm, a depth of 10 ~ 15 cm, and a slight downward inclination.

2.3. 1.4 The ground grit chamber, water inlet pipe and water intake well pipe shall be excavated according to the design requirements, and the section size shall be checked in time.

2.3.2 Seepage prevention of cellar body

2.3.2. 1 daub the wall to prevent leakage.

2.3.2. 1. 1 Take cement and loess (the volume ratio of sand, silt and clay is 1: 2: 1) and mix them evenly to make cement nails, which are about 65438+5~8cm long and 2~5cm in diameter.

2.3.2. 1.2 Push the cement nail into the pattern, leaving 3cm outside, and throw the cement cake on the cement nail to make it a whole.

2.3.2. 1.3 Beat the mud cake with a wooden stick continuously to make it closely combine with the cellar wall until all the mud on the cellar wall is solid and smooth.

2.3.2. 1.4 The mortar thickness of the cellar wall is 2cm, 3cm, 4cm and 5cm from top to bottom.

Seepage prevention of cement mortar in 2.3.2.2

2.3.2.2.1Adjust cement mortar and lime mortar. The volume ratio of cement, sand and water in cement mortar is1.0: 2.0: 2.5; The volume ratio of lime, sand and water in lime mortar is 1.0: 1.5: 2.0.

2.3.2.2.2 First, coat the cellar wall with a layer of lime mortar for "priming", and then coat it with cement mortar, with a thickness of not less than 2 ~ 3 cm.

2.3.2.2.3 Where conditions permit, the lead wire mesh can be riveted on the cellar wall with rivets first, or the steel wire can be evenly driven into the cellar wall first, then the lead wire can be connected into the net, and then the surface can be plastered with cement mortar. With the consolidation of cement, it should be compacted to be firm and smooth.

Other seepage control measures in 2.3.2.3.

2.3.2.3.1where the stone is convenient, the cellar bottom and cellar wall can be built with 1: 3 cement mortar, and the joints can be marked with 1: 3 cement mortar.

2.3.2.3.2 The cellar bottom and cellar wall can be bricked with 1: 1: 6 cement, lime and mortar, and plastered with 1: 3 cement mortar.

2.3.2.3.3 Concrete or reinforced concrete can be used for seepage control if conditions permit.

Ground part construction

2.3.3. 1 Pit mouth shall be built with brick or stone platform, 30 ~ 50 cm above the ground, and equipped with lockable wooden cover plate; Conditional hand pump can be set in the pit.

A lead wire mesh trash rack is set at the joint of 2.3.3.2 sandy land and water inlet pipe to prevent sundries from flowing in.

2.3.3.3 inlet pipe should be extended into the cellar, and lead wire head should be set at the outlet of the cellar wall to prevent water from washing the cellar wall.

2.4 Water cellar management

2.4. 1 After the completion of the water kiln, a proper amount of water should be put in. When formally storing water and taking water, the water cannot be completely pumped out to prevent the cellar wall at the bottom of the kiln from drying up and cracking.

2.4.2 When collecting surface runoff in the rainstorm, there should be a special person on-site to watch, and the water level in the cellar should not exceed the design water level (part of the cellar and water kiln) to prevent the water storage bubbles at the top of the dry cellar and water kiln from collapsing.

2.4.3 Pit cover plate should always be covered and locked to prevent sundries or people and animals from falling into it.

3 Laochi

3. 1 Waterlogging Pool Planning

3. 1. 1 total storage capacity of the waterlogging pond

3. 1. 1. 1 can meet the drinking water demand of livestock.

3. 1. 1.2 to meet the consumption of non-drinking water for residents.

3. 1. 1.3 Reduce soil erosion of roads and gullies.

3. 1. 1.4 Analyze the balance between supply and demand of inflow and water demand.

3. 1.2 Type of waterlogging pond and capacity of single pond

3. 1.2. 1 general waterlogging pool. A road system with multiple branches scattered along the way, with a single pool capacity of 100 ~ 500m3.

3. 1.2.2 Large waterlogging pool. It can store a large amount of water in villages and towns, and the capacity of a single pool is thousands to tens of thousands of cubic meters.

3. 1.2.3 Road ditch water storage weir. Where the road surface is lower than the two sides of the ground and a ditch with a depth of 1 ~ 2m is formed, the road should be changed to one side of the ground, and small earth dams should be built in sections in the ditch to make ditches as water storage weirs to store storm runoff. The capacity of a single weir depends on the width and depth of the trench, the height of the earth dam and the slope of the road, and is generally 500 ~ 1000m3.

3. 1.3 location of waterlogging pool

3. 1.3. 1 The waterlogging pond should be located at a place where the roadside is lower than the road surface, the soil quality is good, and there is enough surface runoff during the rainstorm, and it is more than 10m away from the ditch head and ditch side.

3. 1.3.2 Large waterlogged pool sites should focus on building pools with sufficient capacity and sufficient runoff sources.

3.2 Waterlogging pond design

3.2. 1 general waterlogging pool

Mostly soil, the depth is 1.0 ~ 1.5m, and the shape varies with the terrain. The diameter of circular waterlogging pool is10 ~15m, and the side length of square and rectangle is10 ~ 20m. The surrounding slope is 1: 1.

3.2.2 Large waterlogging pool

2 ~ 3m deep, 20 ~ 30m round diameter, 30 ~ 50m square and rectangular sides, 70 ~ 100m extra large. The peripheral slope ratio of soil is 1: 1, and the peripheral slope of lining stone (or brick-concrete slab) is 1: 0.3. If the waterlogging pool is not on the roadside, the diversion channel should be reformed to introduce road runoff into the waterlogging pool. In order to prevent too much flood from entering the pool, water intake facilities should be set up in front of the pool inlet.

3.2.3 Road ditches and water storage weirs

Small earth dams are generally 1 ~ 2m high or 3 ~ 5m wide, with crest width 1.5 ~ 2.0m, upstream slope 1: 1.5, and downstream slope 1: 1. The catchment area, inflow and storage capacity of each water storage weir in the ditch should be accurately calculated to ensure that a series of water storage weirs in the ditch can store the next storm runoff at the design frequency.

3.3 Waterlogging Pond Construction

3.3. 1 Generally, the waterlogged soil pool should be excavated according to the design size, and the excavated soil can be made into a cofferdam (water intake) to increase the water storage capacity. Clay should be used to prevent leakage at the bottom of the pond. If tiny cracks are found, they should be grouted in time.

3.3.2 If large waterlogging ponds need to be paved with stones, they should be paved according to the requirements in 4.2.

3.3.3 The small earth dam of Lugou water storage weir shall be compacted by layers, and the dry density shall not be lower than 1.4t/m3.

3.4 Waterlogging Pool Management

Dredging shall be carried out once every 2 ~ 3 years, and special personnel shall be assigned for on-site inspection during the rainstorm. When problems are found, they should be dealt with in time.

4 Utilization of mountain spring water

4. 1 planning

Drinking for people and livestock is 4. 1. 1.

Build a well or a pool near the spring outcrop to store water.

4. 1.2 is used to irrigate small plots of land.

4. 1.2. 1 Utilize the spring water outcropped on the hillside. Repair the diversion canal (section 0. 1 ~ 0.2m2) at the outcrop of spring water, or bury tile pipes and clay pipes to lead the spring water to a small water area for small border irrigation; Or build a reservoir, store it at ordinary times and use it for irrigation.

4. 1.2.2 Use the spring water in the ditch. It is necessary to build a small masonry roller dam with a height of 3 ~ 5 m in the ditch to raise the water level, and build a diversion channel at one or both ends of the dam to irrigate a small piece of water on the shore.

4. 1.2.3 If a pond dam or reservoir is built in the ditch to store spring water for irrigation or other purposes, a silt dam or sand dam should be built immediately upstream of the pond dam or reservoir to reduce sediment deposition. These measures should be included in the dam system planning of channel control.

4.2 Design

4.2. 1 Small Waters Land Design

4.2. 1. 1 Sloping farmland or gentle slope land on the bank of the ditch should generally be built into horizontal terraces, and the width of terraces varies with the slope of the ground. Please refer to GB/T 16453. 1 Horizontal Terrace Section Design.

4.2. 1.2 The small boundary size is generally 1.5 ~ 2.0m wide and 5 ~ 10m long (consistent with the terrace width). The last irrigation canal should be perpendicular to the small boundary inside the terrace (at the root of the last ridge).

4.2.2 Design of Rolling Stone Dam

4.2.2. 1 Gravity roller compacted dam is generally used, with a dam height of 2 ~ 3m and a trapezoidal section width of1.0 ~1.5m. The upstream slope is about 1: 0. 1, and the downstream slope is about/kloc. If the terrain and geological conditions permit, masonry arch dam can be used to save labor, materials and investment.

Individual masonry dams with a height of more than 5m in 4.2.2.2 have a certain storage capacity, so stability analysis should be carried out, and the design requirements of masonry dams in the local small water conservancy technical manual can be consulted.

4.3 architecture

4.3. 1 The construction of small plots of water can refer to the requirements of horizontal terraces and small irrigation projects, so that the fields are horizontal and the ridges are firm.

4.3.2 Construction of Roller Compacted Rock Dam

4.3.2. 1 foundation cleaning: extend upstream and downstream according to the width of dam bottom 1.0m, and extend upstream according to the height of both ends of dam body 1.0m, so as to remove silt, rubble and other sundries at the bottom of ditch and bank slope until undisturbed soil foundation or bedrock.

Masonry in 4.3.2.2: The dam body is made of all materials and stones, and it is grouted upward layer by layer. The stone is about 0.5m long, 0.3m wide and 0.3m thick, with the same size.

4.4 management

4.4. 1 A well platform and a workover bay should be built for drinking water wells for people and livestock, so as to keep the well platform and the workover bay clean and prevent surface runoff from entering during rainstorm.

4.4.2 Small water areas, rolling dams, diversion canals, etc. after heavy rain. Should be fully inspected, if there is water damage should be repaired in time.

Second, understanding and implementation

China's Loess Plateau is characterized by serious soil erosion, drought and water shortage, and lack of groundwater resources. In some areas, it is difficult for people and animals to drink water, let alone irrigate the land. In order to improve people's living conditions and solve the problems of drinking water and land irrigation for people and livestock in arid and semi-arid areas in the north and local arid and semi-arid areas in the south, it is one of the effective ways to intercept and utilize the runoff generated by pavement and ditch bottom during rainfall. This part mainly stipulates the technical requirements for the planning, design, construction and management of small water conservancy projects such as puddles (dry wells), waterlogging ponds and mountain spring water utilization. The purpose of building these small water conservancy projects is to control soil erosion on the one hand, and to make use of limited water resources on the other.

Compared with the original standard, the new standard has also made the following modifications:

(1) The name of Article 9 of the original standard was changed from "Basic Provisions" to "General Provisions", with the same intention as the previous chapter.

(2) Delete "designing rainstorms with different frequencies and histories according to different rainfall conditions in different places" in the original standard 9.6. Because in the first half of 9.6, it has been explained that the design standard is10 ~ the maximum rainfall in 20 years is 3 ~ 6h, which is already an interval concept, so the deleted part need not be repeated.

(3) Delete the redundant language and characters in the original standard. For example, the phrase "prevent scouring" in 9.7. 1, "store water for rainy days" in10.3.2, and "ensure safety and sanitation" in 10.4.3.

(4) Change the last sentence of 9.7.2 from "increasing rainfall flow" to "increasing rainfall collection". Because this paragraph mentioned earlier is laying concrete or plywood to collect water, the purpose is to increase rainfall collection, not rainfall flow.

(5) Delete the sentence "Water pits are divided into well pits and kiln pits" in the original standard 10. 1.2. Because in the following description, these two kinds of water cellars are introduced separately.

(6) In the original standard 10. 1.2.2, "There are cliffs with solid soil along the highway, and pit-type water cellars can be built where large water storage capacity is needed, and the volume of single cellars is greater than 100 ~ 200m3". The last sentence is changed to "the capacity of a single pit is greater than1100m3". Remove the upper limit of cellar capacity to leave room for cellar capacity construction.

(7) Delete the sentence "30 ~ 50 cm away from the cellar wall" in the original standard 10.3.3 "The water inlet pipe should extend into the cellar wall, and a lead wire head should be set at the outlet of the nozzle to prevent the water flow from damaging the cellar wall".

(8) Delete the text in the original standard 1 1, that is, "it is mainly built on the roadside (or near the road, or in the reconstructed road hutong) to intercept road runoff and prevent road scouring and ditch head from advancing; At the same time, it can be used for drinking and washing animals. " The standard language emphasizes conciseness and is not used for noun interpretation.

(9) Delete the part "to 20 ~ 30m" in the original standard11"side length of square and rectangle 10~20m ~ 20m to 20 ~ 30m".

(10) Delete the original standard 12. 1 "Take different utilization measures according to the outcrop position and use of springs between hills".

Third, examples.

The role of water cellar in small watershed management is remarkable. It is a small water conservancy project with simple construction, remarkable effect and wide application range, which is worth popularizing. The function of water cellar dry well in small watershed management is reflected in the following aspects; (1) flood storage to reduce soil erosion. (2) provide water. Carry out small watershed management such as planting trees, planting medicinal materials, sowing, breeding and spraying drugs. , all need a lot of water, and water cellar can just solve this problem. (3) Solve the problem of drinking water for people and livestock. The water quality of the dry well in the cellar is good, and it is completely drinkable for people and animals. Conditional places can also make use of the natural drop in mountainous areas, install pipelines, connect with water cellars, and introduce water into farmers' homes to form "tap water for dry wells in water cellars".

Example 1: study on water cellar in loess area of China.

Rainfall is concentrated and there are many heavy rains in the loess area of China, and the rain supply is seriously out of balance with the growth and development period of crops. For example, the hilly areas in Linfen City, Shanxi Province account for more than 70%, mainly agricultural production. The average annual rainfall in mountainous areas is 550 mm, and the rainfall is unevenly distributed during the year. The rainfall from June to September accounts for 70%, which varies greatly from year to year. The ratio of the maximum value to the minimum value of annual rainfall is 2.93∶ 1. In addition, serious soil erosion caused poor soil conditions and weak water storage and moisture conservation capacity, which led to long-term instability of rain-fed agricultural production in loess areas. However, the loess area has deep soil, strong water storage capacity, rich land and light and heat resources, and great natural production potential, which fully shows that rain-fed agriculture in loess area will have great development potential as long as the water resources problem is solved. There are four common water storage facilities in loess area: water cellar, water kiln, pool and waterlogging pool, among which water cellar is the most popular. The volume of water cellar used for drinking water for people and livestock is 15 ~ 30m3, and the volume of water cellar used for rainwater harvesting and irrigation saving or supplementary irrigation is generally 50 ~ 15~30m3.

1. Design and construction of kiln water cellar

At the cellar site, dig down the tunnel from the downhill corner, or build a kiln several meters deep with natural steep cliffs. The rise-span ratio of kiln arch is 1∶3, and the span depends on the soil quality. The height of kiln arch is about 1.5m, and the depth of vault from the ground is generally more than 3m. Kiln arches are divided into rigid materials and soil arches. If concrete is used, the kiln arch foundation shall be made of concrete or brick first, and the concrete arch ribs with cross section size of 1 5cm shall be made at equal intervals from1to1.5m. After plastering 1cm with grass mud, use 100. If bricks are used, the base course of 20cm×30cm shall be made first, the brick arch shall be built with 75 cement mortar, and plastering shall be done with cement mortar or lime soil and grass mud. Natural soil arch shall be leveled with lime soil, grass mud or cement mortar to prevent the soil layer from peeling off. The treatment of kiln arch depends on the soil quality and the economic ability of farmers. After the arch of the kiln was repaired, the pit was dug down. The upper edge of the pit should be 5 cm away from the bottom of the kiln arch. The kiln pool is trapezoidal, with an upper opening width of about 4m, a depth of about 3m, a bottom width of about 3m and a length of 6 ~ 10m. After the anti-seepage treatment is completed, the soil inlet of the kiln arch in the roadway is closed with bricks. The water intake should be selected in the excavated roadway to minimize the height of the water intake and effectively protect the kiln arch. For example, take water from the top, make a closed kiln mouth well platform, and plaster the kiln mouth wall with 100 cement mortar, which is closely connected with the top of kiln arch.

2. Seepage prevention of cellar body

Different structural types of water cellars have different anti-seepage treatment methods, such as bottle-shaped and spherical thin-walled lined water cellars, cement mortar and cement mortar can be used for anti-seepage treatment. Covered bowl-type, teacup-type, cylindrical-type and kiln-type water cellars can be impervious by pouring concrete and masonry.

(1) cement seepage control. Dig a small hole (round hole) with a big hole on the pit wall, the hole is slightly upward and has a certain inclination angle. The code eye is 7cm in diameter, with a depth of 10 ~ 65438+20~25cm and a spacing of 20~25cm, which is zigzag. Fully mix the crushed and sieved cement softened with water, make it into a rod shaft with a diameter of 7cm and a length of about 30cm, nail it into the code hole and fill it, flatten the cement shaft outside the code hole to connect the cement of each code hole into blocks, hammer it with a mallet, compact it, flatten it gradually, and brush the surface with hemp water or black alum water after leveling and polishing. The bottom of the cellar is leveled and compacted with 20 ~ 30cm thick cement, which is closely combined with the cement of the cellar wall, and scoured slate is paved. Cement seepage control has the characteristics of low cost and good drinking taste, but the cement is easy to dry and fall off, and the storage capacity of the cellar is small (there is no water in the neck of the arch cellar).

(2) Cement mortar seepage control. Dig code holes with a diameter of 10cm, a depth of 10cm and a spacing of 30cm on the cellar wall (the bowl-shaped cellar can dig annular grooves of 10cm× 10cm in the horizontal direction, and at the same time, it can evenly dig six10cm×/kloc in the vertical direction. (2) Plaster with No.75 100 cement mortar twice 1.5cm (the mortar is tightly connected with the material yard, belt and rib groove); (3) surface brush 1 ~ 2 times of cement slurry. After the cellar bottom is compacted and leveled with 20cm thick fully mixed cement, it is plastered with 100 cement mortar (3cm thick) or poured with 150 concrete (10 ~ 20 cm thick); The corner where the cellar wall is combined with the cellar bottom shall be plastered with15cm×15cm; The dosage of impermeability agent is 5% of the weight of cement in mortar. Cement mortar seepage-proof water cellar has good performance, high quality, not easy to damage and convenient management.

(3) Seepage prevention by pouring concrete. When the water cellar adopts lightweight concrete wall, the concrete on the side wall and the concrete on the bottom of the water cellar should be poured into a whole. The treatment methods of the joint surface are as follows: ① Brush the concrete surface with steel wire or drill air holes (100/m2) after pouring concrete for 24 hours; (2) Remove sundries and spread 2 ~ 3 cm thick mortar. If the gravity pit wall is used, there should be a settlement joint between the side wall and the bottom plate. The settlement joint is four layers of linoleum, and both sides are coated with asphalt. When building with precast concrete blocks, the clods should be made into a trapezoid with the outer ring slightly larger than the inner ring to form a circle.

(4) Anti-seepage of mortar masonry. When mortar masonry is used to prevent seepage, mortar masonry should be used in the construction. When laying, it should be "flat, stable, tight and full": flat-the elevation of each floor is required to be raised; Steady-the stone should be stable; Tightness-the gap between stones should be as small as possible; Full slurry should fill the gap to prevent dry joint and virtual joint. Attention should be paid to mortar masonry: ① After the initial setting of mortar, stones should not be knocked on the masonry to prevent cracks; (2) The stone with large thickness should be laid from the peripheral edge, and the facing stone positioned in rows and columns should be hard and flat; (3) The thickness of each layer of masonry is about 30cm, and every three layers of masonry should be horizontally tested 1 time, and the upper and lower joints of masonry should be avoided.

The irrigation of high-level spring cascade well group is a rational development and flexible application of local water resources on the basis of developing rainwater harvesting and irrigation saving in arid mountainous areas. It has the characteristics of less investment, quick effect, little influence by seasonal changes and stable operation and management. It is a one-time investment and long-term benefit project to help people get rid of poverty and become rich.

Example 2: Using high-level spring water to develop cascade pit water storage irrigation in mountain platform.

1. Natural conditions

Panshan Village, Jinji Township, Qingshui County is located in the arid area of the shallow mountain area in the southwest of Qingshui County, with an altitude of 1200 ~ 1600 m, an average temperature of 7 ~ 8℃, an average annual precipitation of 542 mm, 795 people in the village, an area of 3,220 mu of cultivated land and 2,440 mu of grain fields. Per capita annual income in 860 yuan, people's life is difficult. According to the field investigation, there is a spring in the upper reaches of Xifanggou near the village, which is 1 12km away from the large-scale aquaculture area and 1390m above sea level. The measured water yield is 44m3/d, and the annual water supply is1160 million m3. Centralized contiguous irrigation area is 480 mu. According to the water-saving irrigation experiment in similar areas, the most critical irrigation methods are winter irrigation, spring irrigation and summer irrigation, and the irrigation quota is calculated at per mu 10m3. The water demand of the whole irrigation area is 1 1440 m3, and the water supply can meet the irrigation demand. Therefore, it is planned to draw spring water from Xifanggou, manage it according to the distribution area of mountain terraces in the irrigation area, build cascade water storage pits, develop water-saving irrigation, and ensure centralized irrigation of 480 mu of farmland. The remaining scattered plots will build hillside rainwater harvesting fields year by year, develop rainwater harvesting irrigation, increase irrigation area and improve economic benefits.

2. Project implementation plan

Buried with < < 25mm hard plastic pipes, the spring water will be transported to the planned contiguous irrigation area. According to the distribution area of mountain platform, a five-level water storage cellar group will be built, and the water storage capacity of each cellar is designed to be 30m3. Each cellar will be recycled three times a year and irrigated with 3 mu of land each time. There are 30 first-class pits with an irrigation area of 90 mu; There are 26 secondary pits with an irrigation area of 78 mu; There are 20 third-class pits with an irrigation area of 60 mu; There are 49 fourth-class pits with irrigation area of 147 mu; There are 35 five-level pits with irrigation area of 105 mu. Assign a special person to drain water, and go through the formalities of closed pit drainage of pit group in time. In order to ensure long-term day and night water storage, the main pipeline is equipped with a first-class fork pipe into the cellar group, and then with a second-class fork pipe into the cellar. Hard plastic pipes < < 50mm are used in series at the highest water level limit between cellars to control the highest water level of each cellars.