CN211946472U

CN211946472U - Local heavy-gradient ecological ditch

Info

Publication number: CN211946472U
Application number: CN201922436424.3U
Authority: CN
Inventors: 尹庆; 聂毅; 徐瑞萍
Original assignee: Guangzhou City Construction College
Current assignee: Guangzhou City Construction College
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-11-17
Anticipated expiration: 2029-12-30

Abstract

The utility model provides a local large-gradient ecological ditch, which comprises an equal-height excavation section and a steep-slope section which are connected in sequence, and is characterized by also comprising a step rolling dam, a slow-flow pool short dike and a choked flow dike which are arranged on the steep-slope section in sequence along the water flow direction; the step rolling dam is provided with at least one step, the upstream surface of the step rolling dam is provided with a one-way slope, and the drainage surface of the step rolling dam is provided with a plurality of multi-stage water drop channels; and the low dike of the slow flow pool is provided with a drainage hole. The utility model discloses the ecological irrigation canals and ditches of local heavy slope can slow down the rivers in the ecological irrigation canals and ditches at the torrent section, thereby effectively reduce ecological irrigation canals and ditches at the great region of the slope and lead to the too big problem of the whole velocity of flow of ecological irrigation canals and ditches because of the velocity of flow is too big.

Description

Local heavy-gradient ecological ditch

Technical Field

The utility model relates to an ecological irrigation canals and ditches of local heavy grade.

Background

1. Overview of ecological ditches

The ditch is an important component of a farmland system and is a channel for converging farmland surface runoff into lakes and rivers. A farmland drainage ditch having bottom mud and in which aquatic plants grow is generally called a farmland ecological ditch. The ecological ditch is provided with a plant-sediment-microorganism system, so that the ditch can play a similar function as the ecological wetland in the base flow period of slow water flow.

In the ecological ditch, the concentration of nitrogen and phosphorus carried in runoff can be effectively reduced through the actions of silt interception, plant absorption, microbial decomposition and the like, and the effects of 'three-removal' (removal of garbage, silt and weeds) and 'three-interception' (interception of sewage, silt and floating materials) are achieved.

China is one of the countries with the largest fertilizer application amount in the world, but the utilization rate of nitrogen and phosphate fertilizers in farmlands is not high all the time, and is about 30-35% and 10-20% by statistics of related researches. The nitrogen and phosphate fertilizers applied to the farmland can enter surface water and underground water due to rainfall, seepage and other ways to cause pollution to the parts which are not absorbed and utilized by crops. The control measures of agricultural non-point source pollution are mainly divided into source control and tail end treatment, wherein the source control is the most effective. In source control, plant buffer zones, artificial wetlands, ecological ditches and the like are the most common methods. The ecological ditch is more suitable for popularization and application in rural areas due to low construction cost and high pollution removal efficiency.

2. Problems existing in ecological ditches in southern hilly farmland areas

Generally, in order to maintain a certain depth of water in an ecological ditch and ensure smooth water flow, the ditch needs to be dug at the same height.

The ditch in southern hilly farmland area leads to the whole slope of ditch great because great difference in relief, just so can make the velocity of water flow in the ditch increase. The large water flow velocity causes that magazines such as silt, weeds, silt, floater and the like carried in the water body can not be effectively settled, and the magazines can not effectively remove impurities from the water body and are not beneficial to the formation of bottom mud. The sediment is the basis of the growth of aquatic plants in the ecological ditch and is also a platform for the growth of various bacteria in the ditch, meanwhile, because a carbon source is needed in the denitrification process in the ecological ditch, deposited organic matters are the main source of a denitrification carbon source under the condition that artificial carbon source supplement cannot be carried out, the denitrification condition is difficult to maintain due to the instability of the carbon source, and the removal rate of nitrate nitrogen and total nitrogen is unstable. Therefore, the ecological ditch is difficult to achieve the expected nitrogen and phosphorus non-point source pollution removal effect due to the large water flow speed.

Therefore, in order to maintain the function of the field ecological ditch in southern hilly areas effectively, it is necessary to provide a local large-slope ecological ditch capable of slowing down the water flow speed, in order to solve the problem that the overall slope of the field ecological ditch in southern hilly areas is large due to the terrain (as shown in fig. 1).

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an ecological irrigation canals and ditches of local heavy slope to solve the ecological irrigation canals and ditches of southern hilly farmland area because the great, the faster problem of velocity of water flow in irrigation canals and ditches of whole slope.

In order to achieve the above object, the utility model provides a following technical scheme:

a local large-gradient ecological ditch comprises an equal-height excavation section and a steep section which are sequentially connected, and is characterized by further comprising a step rolling dam, a slow flow pool short dike and a choked flow dike which are sequentially arranged on the steep section along the water flow direction;

the step rolling dam is provided with at least one step, the upstream surface of the step rolling dam is provided with a one-way slope, and the drainage surface of the step rolling dam is provided with a plurality of multi-stage water drop channels;

and the low dike of the slow flow pool is provided with a drainage hole.

In the utility model, the cross section of the ditch is in a shape of an inverted trapezoid, the upper surface is 2-3 meters wide, the lower bottom is 1-2 meters wide and the depth is 1-2 meters. The utility model discloses in, the slope of steep slope section exceeds 10%.

The utility model discloses in, ladder rolling dam total height is 1/2-2/3 of the whole degree of depth of irrigation canals and ditches, and the upstream face slope 300% -400% of ladder rolling dam, the whole slope 20% -30% of sluicing.

The utility model discloses in, when ladder rolling dam set up a plurality ofly, adjacent ladder rolling dam's difference in height is more than 2 meters.

The utility model discloses in, multistage drop basin is the rectangular pond of a trough-shaped, intersects with the irrigation canals and ditches side slope.

Furthermore, the width of each water drop groove is 0.5-1 meter, and the height difference between adjacent multistage water drop grooves is not more than 0.1 meter; the depth of the groove-shaped long-strip pool is 0.2-0.3 m.

The utility model discloses in, the short dyke height in slow flow pond is the same with ordinary water level height.

The utility model discloses in, the choked flow dyke with the short dyke distance of slow flow pond is 3 meters-4 meters.

In the utility model, the choked flow dyke has the same shape and size with the short dyke of the slow flow pool.

Compared with the prior art, the utility model discloses following beneficial effect has:

(1) the utility model discloses the ecological irrigation canals and ditches of local heavy grade is fit for being applied to the relief complicacy, and the ecological irrigation canals and ditches of newly-built, rebuilding in the great area of relief change especially can slow down the rivers of torrent section in the ecological irrigation canals and ditches, thereby effectively reduces ecological irrigation canals and ditches and leads to the too big problem of ecological irrigation canals and ditches integral velocity of flow because of the rivers velocity of flow is too big in the great region of slope.

(2) The stepped rolling dam arranged in the middle local large-gradient ecological ditch of the utility model can form a deep water area with gentle water flow at the upper end on the one hand, promote the deposition of impurities and the like in runoff, simultaneously promote the layering of water quality in the runoff, and enable high-concentration sewage at the upper layer to descend through the top of the rolling dam; on the other hand, the level drop that the rolling dam lower extreme set up can be effectively to the radial flow efficiency, reduces the potential energy of rivers, and simultaneously, each grade in the multistage drop groove can fully exert the absorption and absorption ability to nitrogen phosphorus, further reduces non-point source pollutant nitrogen phosphorus.

(3) The local large-gradient ecological ditch can effectively slow down the water flow loss of the large-gradient section of the ecological ditch, can provide a better migration path for the aquatic animals of migration, and reduces the death rate of the aquatic animals of migration; meanwhile, in the dry season, as long as the most basic flow exists in the ecological ditch, the deep water area formed by arranging the rolling dam can be ensured to exist and maintain a water body with a certain depth, water taking and living places can be created for protozoa, and the phenomenon of large-area death caused by water shortage of the protozoa in the ecological ditch in dry seasons can be avoided.

Drawings

FIG. 1 is a schematic view of the slope of the whole ecological ditch in southern hilly areas;

FIG. 2 is a schematic view of the overall structure of a local steep ecological ditch according to an embodiment of the present invention;

fig. 3 is a top view of a local steep ecological ditch according to an embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view taken along line A-A of the local steep ecological trench of FIG. 3;

the reference numbers in the figures are as follows: 1-local large-gradient ecological ditch; 2-step rolling dam; 3-a multi-stage drop chute; 4-slow flow pool short dike; 5-a choke bank; 6-step; 7-a sedimentation tank; 8-slow flow pool; 9-denitrification carbon supplement tank; 10-ditch bottom mud; 11-planting substrate; 12-pebbles; 13-Artificial carbon source.

Detailed Description

The present invention is further described below with reference to specific examples so that those skilled in the art can better understand and implement the technical solution of the present invention.

The local large-slope ecological ditch 1 shown in the figures 1-4 is the same as a common farmland ditch in section and comprises an equal-height excavation section and a steep slope section.

The upper surface of the trapezoid is about 2-3 meters wide, the lower bottom of the trapezoid is about 1-2 meters wide, and the depth of the trapezoid is about 1.5 meters. One or more step rolling dams 2 are arranged at the position where the gradient of the steep slope section of the ditch is large (the gradient exceeds 10%), and the height difference of each step rolling dam 2 needs to be ensured to be more than 2 meters so as to ensure enough space. In this embodiment, the number of the step dams 2 is 1. The total height of the step rolling dam 2 is 1/2 of the whole depth of the ecological ditch; the slope of the upstream surface of the stepped rolling dam 2 is about 300 percent and is a complete one-way slope, the one-way slope and two side slopes of the channel form a sedimentation tank 7 with the depth of about 1 meter above the water flow, and emergent wetland plants (such as reeds and the like) and submerged plants (such as armpit and the like) with larger body types are planted in the sedimentation tank 7; the integral gradient of the water drainage surface of the stepped rolling dam 2 is about 20%, the stepped rolling dam is composed of a plurality of multistage water dropping grooves 3, the width of each stage of multistage water dropping groove 3 is about 0.5 m, the integral height of the adjacent multistage water dropping grooves 3 is gradually reduced, the height difference is not more than 0.1 m, the water dropping height is not more than 0.1 m, each stage of multistage water dropping groove 3 is a groove-shaped long strip pool, the groove-shaped long strip pool is intersected with the side slope of the ditch, the depth of the groove-shaped long strip pool is 0.2 m, substrates 11 are backfilled and planted in the groove, shallow wetland plants such as canna, hemerocallis and the like are planted, and the; a slow flow pool short dam 4 is arranged at a distance of about 2 meters from the water discharge direction of the step rolling dam 2, the height of the slow flow pool short dam 4 is the same as the height of a normal water level, generally about 0.2 meter, and a plurality of discharge holes soaked below the normal water level are arranged on the body of the slow flow pool short dam 4; a slow flow pool 8 is formed between the slow flow pool short dike 4 and the multi-stage water drop groove 3 of the stepped rolling dam 2, the bottom of the slow flow pool 8 is hardened, and pebbles 12 with the particle size of 5-10 cm are fully filled in the pool; a choke bank 5 is arranged at a position about 3 meters downstream of the slow flow pool short bank 4, the cross section of the choke bank 5 is the same as that of the slow flow pool short bank 4, but a drainage hole is not arranged; the slow flow pool short dike 4 and the flow blocking dike 5 enclose a denitrification carbon supplement pool 9 together, and the channel side slopes on the two sides of the denitrification carbon supplement pool 9 are provided with steps 6, so that personnel can conveniently replace carbon sources of the carbon supplement pool.

The working principle of the local large-gradient ecological ditch for treating the farmland non-point source polluted water body is as follows:

after the stepped rolling dam 2 is arranged in the ditch, a sedimentation basin 7 with deeper water depth (about 1/2 of the depth of the ditch, generally about 1 meter) and more gentle water flow is formed together with two side slopes of the ditch in the water facing direction. In the sedimentation tank 7, because the water flow is gentle and the water surface is large, sundries and particles in the water can be effectively settled, the sundries and the particles are deposited to form a bottom mud layer with large thickness together with the original planting soil, and because the sedimentation tank 7 has large area (unchanged width but long length), the sedimentation tank 7 is suitable for planting large wetland plants such as reeds and submerged plants such as watermifoil and the like; simultaneously, because in the darker region of water level, receive the water body that non-point source pollutant nitrogen phosphorus pollutes, especially pollute heavier water, can obviously demonstrate the layering, nitrogen phosphorus content can obviously be higher than the water nitrogen phosphorus content on low water layer in the water on high water layer, consequently, the water through the sedimentation tank, through first step's deposit, the back is clear away to nitrogen phosphorus, the layering that carries on of water meeting nature, untreated more nitrogen phosphorus pollutant will be discharged downwards through ladder rolling dam 2 in the upper water, thereby avoid depositing of nitrogen phosphorus pollutant.

Through preliminary debris, the farmland sewage that particulate matter subsided and nitrogen phosphorus was clear away, through the multistage drop tank 3 of the top flow direction of ladder rolling dam 2, each grade in multistage drop tank 3 all is equivalent to a miniature constructed wetland, rely on the matrix of drop step upper trough shape rectangular pond in and the little volume wetland plant of planting in the matrix, absorb the absorption to partial nitrogen phosphorus element in the farmland sewage that flows through, plant roots carries out the oxygenating in to the matrix, promote the emergence of partial nitrogen element nitration. Meanwhile, the height of each level of the layered water drop is controlled to be about 0.1 meter, and the plants in the tank buffer the water flow, so that the water flow speed is not very high, therefore, the downstream migratory fishes can safely and quickly migrate, and the improvement of an upstream ecosystem is promoted.

The slow flow pool 8 has the function of buffering farmland sewage flowing down through the stepped rolling dam 2 to form a gentle runoff, bubbles in water are reduced, the water body is prevented from carrying the bubbles, the water flowing through the slow flow pool enters the denitrification carbon supplement pool 9 through the drainage hole in the embankment body of the slow flow pool short embankment 4, so that the contact between the water flow and air can be reduced, the excessive high oxygen content in the water is avoided, the efficiency of denitrification of nitrate nitrogen or nitrite nitrogen contained in the water body in the next step is influenced, the flowing of the water flow from top to bottom can be reduced, and the density of a manual carbon source supplement is influenced. The cobblestones 12 fully arranged in the slow flow pool 8 can play a role in slowing down water flow, can avoid full contact between the water flow and air, and can also be used as a growth foundation bed of bacteria.

In the denitrification carbon supplementing pool 9, a carbon source is manually filled, the organic carbon source in the carbon source can be bark, wood chips, fallen leaf compost, newspaper, wheat straw, sawdust, cotton, pea stalks and the like, the inorganic carbon source is mainly formed by mixing elemental sulfur, a sulfur-lime mixture and the like, the artificial carbon source needs to be compacted for preventing the carbon source from flowing away along with water flow, a dense fishing net or a piece of linen cloth with good water permeability is used for covering the artificial carbon source 13, a heavy object such as stone is put on the artificial carbon source, the artificial carbon source 13 is completely soaked by water, after the carbon source is manually supplemented, the sewage flowing down through the stepped rolling dam 2 is subjected to nitrification in an oxygen-rich environment, nitrate nitrogen or nitrite nitrogen generated by nitrification in the 4 denitrification pool is utilized in an anaerobic state, the denitrification condition is maintained, the denitrification reaction is fully generated, and the nitrogen element in the water body is efficiently removed; meanwhile, the artificially supplemented carbon source has extremely high body surface ratio and can also partially adsorb phosphorus elements.

The above embodiments have been explained in detail the different implementation processes of the present invention, but the embodiments of the present invention are not limited thereto, and the ordinary skilled person in the art can realize the object of the present invention according to the contents disclosed in the present invention, and any improvements and modifications based on the concept of the present invention fall within the protection scope of the present invention, and the specific protection scope is subject to the description of the claims.

Claims

1. A local large-gradient ecological ditch comprises an equal-height excavation section and a steep section which are sequentially connected, and is characterized by further comprising a step rolling dam, a slow flow pool short dike and a choked flow dike which are sequentially arranged on the steep section along the water flow direction;

and the low dike of the slow flow pool is provided with a drainage hole.

2. The local steep ecological ditch of claim 1, wherein the slope of the steep section exceeds 10%.

3. The ecological ditch of local heavy slope of claim 2, characterized in that, the total height of the step rolling dam is 1/2-2/3% of the whole depth of the ditch, the upstream slope of the step rolling dam is 300-400%, and the whole slope of the drainage surface is 20-30%.

4. The ecological ditch of local heavy slope as claimed in claim 1, wherein when the step rolling dam is provided in plurality, the height difference between adjacent step rolling dams is more than 2 m.

5. The local heavy-gradient ecological ditch according to any one of claims 1 to 4, wherein the multistage drop trough is a groove-shaped strip pool intersecting with the side slope of the ditch.

6. The ecological ditch of local heavy slope of claim 5, characterized in that, the width of the drop chute is 0.5 m-1 m, and the height difference between adjacent multistage drop chutes is not more than 0.1 m; the depth of the groove-shaped long-strip pool is 0.2-0.3 m.

7. The ecological ditch of local heavy slope as claimed in claim 5, wherein the height of the shallow dam of the slow flow pond is the same as the height of the normal water level.

8. The local steep ecological ditch of claim 6 or 7, wherein the distance between the choked dam and the slow flow pool low dam is 3-4 m.