Patent ID: 12234617

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. According to the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without consuming any creative work fall within the protection scope of the present application.

An objective of the present application is to construct a flood storage area ecological wetland, and a flood storage area can operate as an ecological wetland in the case of no excessive floods. In the present application, the construction method for the flood storage area ecological wetland aims at improving agricultural production, water purification and biodiversity protection.

The method provided by the present application will be described in detail below with reference to specific embodiments.

I. To Improve Agricultural Production.

1.1 A land type in a flood storage area is obtained according to survey data of land resources.

In transformation of the flood storage area, the area and the spatial distribution of a basic farmland area shall remain unchanged as a principle, except for necessary engineering construction land in the flood storage area. For example, in order to ensure the safety of flood storage in the flood storage area, it is necessary to occupy the basic farmland area for dike reinforcement and construction of flood-invading and flood-retreating buildings. The basic farmland area may be occupied under the premise of legality.1.2 A planting object of the basic farmland area is determined by following policies related to basic farmlands in China according to a climate and an environment of the flood storage area.

Taking a Shiba Lianwei flood storage area as an example, its internal basic farmland area is 20,000 mu, accounting for about 50% of the total area of 41,400 mu of Shiba Lianwei. The planting objects identified in this basic farmland area include rice and corn.1.3 A wetland engineering layout of the flood storage area is carried out in line with local conditions by following a principle of minimum engineering quantity according to a landform, a land type and a regional status quo of the flood storage area. The regional status quo includes original river system distribution, planted vegetation, and building conditions of the flood storage area.

Based on overall positioning of the flood storage area of the ecological wetland, on the basis of satisfying a flood storage function and according to the existing farmland texture and water system ditch layout in the flood storage area, the ecological wetland and the ecological agriculture are combined, by the measures of farmland water system connection, small and micro wetland construction and water ecosystem restoration, thereby enriching the wetland biodiversity and serving a purification function of bypass wetlands while maintaining a certain grain yield. Specifically, a low-lying area where rice is planted is taken as a multi-paddy-field wetland area, a low-lying area being a water surface is taken as a small and micro wetland, and a high-lying area is taken as a forest and grass wetland area.

Then, for solving the problems of different original farmland ownerships, different field sizes, uneven field heights, the same channel for water inlet and outlet, and low agricultural efficiency in the flood storage area, the basic farmland area in the flood storage area is transformed as follows.

First of all, land leveling is performed on the field to form a multi-stage terraced wetland with drop-offs, including but not limited to:(1) small fields with small widths are combined into a large field, and the combined field should be controlled to 100 m to 200 m in length, 100±10 m in width and 1.5 hm2to 2.5 hm2in area, the field with a small width referring to a field with a width less than 100±10 m;(2) land leveling is performed on the field with a land elevation difference of more than 20 cm; and(3) for individual fields of greater lengths, nested ditches are disposed in a paddy field at preset intervals (for example, 100 m) to increase the uniformity of water distribution, the individual field of a greater length referring to a field with a length greater than 200 m.

In a preferred solution, a filter material (for example, zeolite) is laid in the nested ditch to remove nitrogen and phosphorus from water.

In this embodiment, the nested ditch is 3 m in width and 0.6 m in depth, gabion boxes are disposed on two sides of the nested ditch; and inside the nested ditch, zeolite with a particle size of 4 cm to 6 cm is laid on two sides, and zeolite with a particle size of 1 cm to 3 cm is laid in the middle.

Secondly, original ditches in the field are dredged, such that the ditches are spaced at intervals of 100 m to 200 m, and a water intake canal and a water exhaust canal are separated from each other.

By adopting the above measures, the original texture of low-lying paddy fields surrounded with dikes can be preserved to the greatest extent, and at the same time, the agricultural production efficiency and the agricultural production output can be improved.1.4 A water inlet and outlet system of the flood storage area ecological wetland is constructed based on an intake and drainage separation principle.

In this embodiment, an overall water inlet and outlet system in the flood storage area is designed in the following way: using a total wetland water intake gate and a built river gate of the flood storage area for self-flow diversion of water, causing water to first enter a dyke and settle and be purified in a stabilization pond, and then enter a wetland water distribution main canal to dispense water for each wetland unit from top to bottom, and finally, pumping and discharging purified river water back to an original river through a water drainage station.

In this embodiment, an water inlet and outlet system of an internal unit is designed in the following way: dredging a current water intake canal and a current water exhaust canal, and distinguishing a water intake ditch from a water drain ditch; for an area where a water system fails to be communicated, connecting the ditches by means of excavation to ensure smooth water inlet and outlet; providing a water inlet control sluice gate at a water inlet to control the water intake; and providing a water outlet control sluice gate at a water outlet end of a water outlet branch canal to control a water level of the wetland. A total of 63 water inlet branch canals with a total length of 55.6 km and 42 water outlet branch canals with a total length of 43.1 km are provided.

II. To Improve Water Purification.

According to the water purification target of the flood storage area of the ecological wetland and the current pollution situation inside the flood storage area, the design process and the overall layout of the wetland are determined. When the pollution load inside the flood storage area is high and the water purification target is not reached, the purification capacity may be affected and the pollution load inside the flood storage area needs to be reduced. Then, the following ecological wetland construction steps are executed.2.1 A pollution source is investigated inside the flood storage area, the water quality of ditches of pit-ponds inside is monitored, and a main pollution load is analyzed.2.2 One or more of the following measures is chosen for implementation according to the main pollution load in a dike: adopting an ecological agriculture planting mode to reduce emissions from the source; transforming a water surface of an existing pit-pond to form a small and micro wetland, and reducing a pollution load nearby; and building an island with silt and treating polluted sediment with an ecological infiltration technology to reduce endogenous pollution in situ.

In this embodiment, the main pollution load in the flood storage area comes from agriculture, so the ecological agriculture planting mode is implemented in the flood storage area. Specifically, adopting the ecological agriculture planting mode includes: laying pebbles at bottoms of a water inlet channel and a water outlet channel, sowing grass seeds in areas above normal water levels of the water inlet channel and the water outlet channel, restoring submerged vegetation in the water inlet channel and the water outlet channel having greater widths, and restoring emergent vegetation on a side slope.

In this embodiment, the particle size of the laid pebbles is 1 cm to 2 cm and the thickness of laying is 0.2 m. The grass seeds are selected from one or more of Bermuda grass, alfalfa,Zoysia japonica, ryegrass and tall fescue, with a specification of 15 g/m2; the submerged vegetation is selected from one or more ofVallisneria spiralis, Potamogeton crispusL.,Myriophyllum spicatum, Hydrilla verticillata, Potamogeton malaianus, Potamogeton pectinatus, Potamogeton maackianusandCeratophyllum demersum; and the emergent vegetation is selected from one or more of reed, lotus, bamboo reed,Pontederia cordata, Iris pseudacorusL., andIris sibirica.

An original water inlet channel and an original water outlet channel in the flood storage area are desilted and dredged to ensure a water-passing function of the original water inlet channel and the original water outlet channel; and for an area with insufficient cross-section, the water passability is ensured by means of expanding excavation and creating a new channel, and herbaceous and aquatic plants, etc. are planted according to the function and the water level of the channel to add a purification function to the channel.2.3 Ecological planting and breeding is carried out in a purification area of the multi-paddy-field wetland, including but not limited to rice and crab co-breeding, rice and fish co-breeding, rice andProcambarus clarkiico-breeding, and rice andMacrobrachium rosenbergiico-breeding, such that the use of pesticides and fertilizers can be reduced on a large scale to reduce the risk of pollution.
III. To Improve the Biodiversity.

In conjunction with the water inlet and outlet system constructed in step 1.4, the existing paddy fields, lotus root ponds, and ditches in the flood storage area are transformed into wetlands having the water purification function, and diversified and healthy wetland systems are created by using habitat restoration and food web structure adjustment and control technologies to increase the species and the quantity of organisms in the flood storage area. Multiple types of wetland habitats include, but are not limited to, a paddy field wetland, a marsh wetlands, a forest and grass wetland, a river wetland and a small and micro wetland.

In this embodiment, the functional zoning in the flood storage area includes a multi-paddy-field wetland area, a marsh wetland area and a forest and grass wetland area. 158 hm2of paddy field wetland and 12.5 hm2of small and micro wetland are restored in the multi-paddy-field wetland area. 239 hm2of paddy field wetland and 8.6 hm2of small and micro wetland are restored in the marsh wetland area. 414.1 hm2of paddy field wetland, 145.1 hm2of corn field, 44.3 hm2of small and micro wetland and 13.4 hm2of forest field are restored in the forest and grass wetland area. The small and micro wetland is mainly obtained by transforming the water surface of the original pit-pond, including: desilting, topographic finishing, water system connection, revetment construction, substrate laying, vegetation restoration and aquatic animal restoration.

The small and micro wetland is obtained by transforming the water surface of the original pit-pond, and can be used for purifying agricultural non-point source pollution. At the bottom of the small and micro wetland, yellow sand with a thickness of 0.06 m and zeolite with a thickness of 0.02 m are laid, in which the yellow sand is medium-coarse sand, and the zeolite has a particle size of 1 cm to 3 cm, a specific surface area of more than 8 m2/g, and a porosity of more than 32%. Infiltration weirs are provided in some small and micro wetlands for water purification. The substrate in the infiltration weir includes zeolite with a particle size of 1 cm to 3 cm and limestone gravel with a particle size of 10 cm to 20 cm.

The revetment of the small and micro wetland may be in the form of a variety of a natural revetment, a wooden pile revetment, a gabion revetment, a riprap revetment and a sandy revetment, which can create diversified habitat conditions.

Planting different types of aquatic plants in open water inside the small and micro wetland can increase the plant diversity in the small and micro wetland and provide habitats for different types of aquatic animals and plants. Wet herbs are planted above the normal water level, mainly selected from Bermuda grass, alfalfa,Zoysia japonica, ryegrass, tall fescue,Arundo donaxvarversicolor, Chinese pennisetum, Cyperus alternifolius, Iris sibirica, etc.

At the initial stage of project construction, an appropriate amount of benthic organisms are put in as an initiating factor of a healthy water ecosystem. The density of the benthic organisms is 5 g/m2based on the amount of water at the normal water level, and the species of the benthic organisms areBellamya aeruginosaandHyriopsis cumingii.

Note: the above descriptions are merely preferred embodiments of the present application and the applied technical principles. It will be appreciated by those skilled in the art that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, but may also include more other equivalent embodiments without departing from the concept of the present application, all of which fall within the protection scope of the present application.