Fish and Aqua

FISH POND CONSTRUCTION, PREPARATION & MANAGEMENT FOR BETTER FISH FARMING IN INDIA

December 17, 2019

7612

by-DR RAJESH KUMAR SINGH ,JAMSHEDPUR,JHARKHAND, INDIA, 9431309542,rajeshsinghvet@gmail.com
& Ritesh Pandey, JAGO KISAN JAGO,7004551516.

Fish pond preparation is the basic and first step in freshwater fish farming. Pond preparation is to be done intensively to enhance the fish production of the pond. Without proper preparation of the pond bottom if we start the fish culture technique it will create a huge problem and production will be of poor quality. In the case of the pond preparation process, good management practices are the basic solution for obtaining better fish yield. Sustainable methods should always be chosen to make pond preparation more suitable for environment-friendly fish farming technique.

Importance of pond preparation in fish farming

The most important component of the fish farming business is to prepare a pond in a proper way. Without the construction of a well-prepared pond, it is not possible to start or run any fish farming business. The importance of pond preparation is given below.

Aquatic plants and animals which are harmful to fish are controlled
Cannibalistic and unwanted fishes are removed
A healthy environment of the pond is preserved
Optimum pH for fish production is maintained
Availability of the feed for the cultured fish is ensured

Types of ponds used in fish farming

Within freshwater fish culture unit, different kinds of pond components are used; they are nursery, rearing, production, segregation and breeding/spawning pool.

The percentage of area covered by these different pond types are given below:

Nursery pond: 3%

Rearing pond: 11%

Production pond: 60%

Segregation pond: 1%

Breeding pond: 25%

Nature of different ponds

Nursery ponds: Shallow

Rearing ponds: Moderately deep

Production ponds: Moderately deep

Segregation pond: Moderately deep

Breeding ponds: Moderately deep

Water level (for larger production ponds): 2-3 meters

Fish Pond construction

Survey

Before constructing the pond, land is surveyed to find out determine its topography.
Marking the area of proposed pond is the first step in the construction of a fish pond.
The natural slope where the main wall is to be built should be ascertained.
The main wall should be marked off at the lower end of the pond, where the slope is the greatest.

Designing

The first step while designing fish ponds should be to study the soil type, topography and water supply.
In designing the fish farm, it should be decided as to where and how many nursery, rearing and stocking ponds are to be constructed.
In case of a fish farm constructed solely for the purpose of seed production, only nursery and rearing ponds may be constructed, with a nominal area for the brood stock ponds.
In case of grow-out farm, more stocking ponds will be constructed to produce table size fish after stocking fingerlings.
For a composite fish farm all three types of ponds are required and their number should be based on the intended stocking density.
Fish ponds should be at least one surface acre in size. Ponds smaller than one acre seldom support a satisfactory fish population over many years. They usually require much more intensive fish management and may not justify the costs.
It is important to know the exact size, maximum depth, average depth, and water volume of the pond. This information becomes useful in calculating the amount of herbicide needed for weed control and the number of fish fingerlings needed for stocking.

Different kinds of pond

Freshwater fish ponds differ according to their source of water, the way in which water can be drained from the pond, the material and method used for construction and the method of use for fish farming. Their characteristics are usually defined by the features of the landscape in which they are built. Ponds can be described as follows.

According to the water source

Ponds can be fed by groundwater:

(a) Spring-water ponds are supplied from a spring either in the pond or very close to it. The water supply may vary throughout the year but the quality of the water is usually constant.

(b) Seepage ponds are supplied from the water-table by seepage into the pond. The water level in the pond will vary with the level of the water-table.

Rain-fed ponds:

Rain-fed ponds are supplied from rainfall and surface runoff. No water is supplied during the dry season. These ponds are often small depressions in impermeable soil, with a dike built at the lower side to retain more water.

Ponds can be fed from a water bodysuch as a stream, a lake, a reservoir or an irrigation canal. These may be fed directly(e.g. barrage ponds), by water running straight out from the water body to the ponds, or indirectly (e.g. diversion ponds), by water entering a channel from which controlled amounts can be fed to the ponds.
Pump-fed pondsare normally higher than the water level and can be supplied from a well, spring, lake, reservoir or irrigation canal, by pumping.

According to the means of drainage

Undrainable pondscannot be drained by gravity. They are generally fed by groundwater and/or surface runoff, and their water level may vary seasonally. Such ponds have two main origins.
Drainable pondsare set higher than the level to which the water is drained and can easily be drained by gravity*. They are generally fed by surface water such as runoff*, a spring or stream, or are pump-fed.
Pump-drained pondsmay be drainable by gravity to a certain level, and then the water has to be pumped out. Other ponds, similar to undrainable ponds, must be pumped out completely. These ponds are only used where groundwater does not seep back in to any extent.

According to the construction materials

Earthen pondsare entirely constructed from soil materials. They are the most common, and you will learn primarily about these ponds in this manual.
Walled ponds are usually surrounded by blocks, brick or concrete walls. Sometimes wooden planking or corrugated metal is used.
Lined pondsare earthen ponds lined with an impervious material such as a plastic or rubber sheet.

According to the construction method

Dug-out pondsare constructed by excavating soil from an area to form a hole which is then filled with water. They are usually undrainable and fed by rainfall, surface runoff or groundwater.
Embankment pondsare formed without excavation by building one or more dikes above ground level to impound water. They are usually drainable and fed by gravity flow of water or by pumping.
Cut-and-fill pondsare built by a mix of excavation and embankment on sloping ground. They are usually drainable, and water, which is impounded within the dikes, is fed by gravity or by pumping.

According to the use of the pond

Spawning ponds for the production of eggs and small fry;
Nursery ponds for the production of larger juveniles;
Brood ponds for broodstock rearing;
Storage ponds for holding fish temporarily, often prior to marketing;
Fattening ponds, for the production of food fish;
Integrated ponds which have crops, animals or other fish ponds around them to supply waste materials to the pond as feed or fertilizer;
Wintering ponds for holding fish during the cold season.

Three basic pond types

Ponds can be conveniently grouped into three basic types depending on the way the pond fits in

with the features of the local landscape.

SUNKEN POND:

The pond floor is generally below the level of the surrounding land.
The pond is directly fed by groundwater, rainfall and/or surface runoff.It can be but is not normally supplemented by pumping.
The sunken pond is undrainable or only partially drainable, having been built either as a DUG-OUT PONDor to make use of an EXISTING HOLLOWor DEPRESSION in the ground, sometimes with ADDITIONAL EMBANKMENTS to increase depth.

BARRAGE POND:

They are created in the bottom of a valley by building a DAMacross the lower end of the valley. They may be built in a series down the valley.
The barrage pond is drainable through the old river bed.
If large floods are present, the excess water is normally diverted around one side of the pond to keep the level in the pond constant. A DIVERSION CANALis built for this purpose; the pond water supply is then controlled through a structure called the WATER INTAKE.
Directly fed from a nearby spring, stream or reservoir, the water enters the pond at a point called the INLETand it flows out at a point called the outlet.
To protect the dike from floods, a SPILLWAYshould be built.

DIVERSION POND:

The diversion pond is fed indirectly by gravity or by pumping through a diversion canal (which becomes the MAIN FEEDER CANAL), from a spring, stream, lake or reservoir. The water flow is controlled through a water intake. There is an inlet and an outlet for each pond.
The diversion pond can be constructed:

either on sloping ground as a cut-and-fill pond;
or on flat ground as a four-dike embankment pond sometimes called a PADDY POND.

It is usually drainable through a drainage canal.

Construction

After the designing, it is necessary to prepare detailed estimates of the items of work to be carried out as per the design.
The approximate cost of construction is also to be estimated.

Construction time

The construction time of the pond is an important factor for pond management.
If the construction of the ponds is completed in summer, the pond can be used for farming immediately for next season (monsoon).

Preparation of the site

The site should be cleared before the construction.
All the bushes and small plants, etc. should be cut and removed along with their roots. The roots should be totally removed; otherwise the leakage problem will arise later on.
If there are any trees near the construction site, it is better to cut the branches overhanging the ponds, so that the sunlight is not blocked and the leaves do not fall in the water.
It is better to have trees near the ponds, but only 5m away from the pond.

Mark out the ponds

When the pond area is cleaned, it is necessary to mark the outlines of ponds and dykes.
Mark out the main wall or dyke and other walls with stakes. The walls should be wide.
Plan the depth of the pond and height of walls.
The walls should always be at least 30 cm higher than the water level for a small pond, and at least 50 cm higher for a larger pond.

Excavation of the pond

It can be carried out either by manual labour or by dozers (JCBs).
The sides and bottom of ponds should be properly finished and trimmed until a good slope for drainage is made.
The pond bottom should usually have a slope of 2-5%.
The most important feature is to have the pond bottom slope such that the pond can be drained.
If the pond site has a natural slope, the dyke or main wall should be constructed at the low level side.
When the pond walls are constructed, the excavated soil can be placed on the top and planted with grass.
This fertile top soil will root grass easily and this will help keep the walls from eroding.
The pond bottom must be cleared by removing small rocks, roots, and stumps to prevent the nets from getting caught and torn during harvesting.

If grass is found in the pond bottom, it need not be removed, because after filling up the pond with water the grass will die and add nutrients to the water.
When the stakes have been established for construction of dykes, about 2′ top soil should be removed as it consists of large amounts of roots and other organic material.
The core trench is cut immediately after the removal of the top soil. If the soil is porous, the seepage problem may arise at a later stage. It would be essential to provide a clay core in order to prevent seepage.
A soil which is a mixture of sand and clay is best.
Pure clay soil will crack and leak.
If pure clay is to be used, it must be mixed with other soil before it can be used.

Turf, humus or peaty soils should not be used.
All stones, wood pieces and other material which may rot or weaken the wall must be removed before building begins.

Construction of dyke

Construction of earthen dyke is always economical.
Soil obtained from digging can be used to prepare the earthen dyke.

Construction of dyke

The filling of earth should be done in layers not exceeding 20 cm in height and consolidate each layer by watering and ramming.
The earth work for the dykes should be thoroughly compacted so that even minor seepage can be checked.
If the fish farmer is economically sound, he can go for stone pitched dykes.
The dykes of a pond should be strong enough to withstand weather action.
In big ponds erosion of dykes is a problem which requires regular attention.
Brick or stone pitching may be provided to arrest erosion of dykes.
Earthen dykes can be protected from erosions with bamboo piling.
Holes should be closed immediately with stiff clay mixed with lime and cementing material and should be compacted properly.
By using concrete blocks, stones or bricks the earthen dykes will be protected more permanently from crab or rat holes.
Side slopes of embankments depend upon the nature of material used for construction. The slopes should be flatter than the angle.
Soil with a lot of clay in it can have a greater slope on the outside wall than on the inside wall.
A typical embankment is built with an outside slope of 1:1 and an inside slope of 1:2.
A slope of 1:2 means that for every increase in 2m width there is a change of 1 m in height.
Once the embankment is constructed, it is better to plant grass on it.
The grass roots help to hold the wall together and prevent erosion of the soil.

Drainage system

A drainage system is used to empty the pond.
It consists of the outlet system for letting water out of the pond and the drainage ditches which carry the water away from the pond.

Drainage of the pond water

The best and easiest way to have a good drainage system is to build the pond in a place which provides a good slope.
The drainage system must be built before the pond embankment because some drainage devices go through the walls.
One of the easiest ways to drain the pond is to place a bamboo or plastic pipe through the base of the wall into the middle of the pond.
The end of the pipe, which is inside the pond, should have a screen over it to keep fish from entering the pipe. The other end of the pipe is plugged with wood or clay. To drain the pond during harvest time, the plug is pulled out.
Other methods of draining the ponds are the siphon and the pump.

Drainage of the pond

Sluice

The sluice can be a screened gate in a water channel going into the pond or drainage gate leading water out of the pond.
The sluice can be made of wood, cement and brick. It can be made up of one or two wooden gates which are removed to empty or fill the pond.
A sluice also has a screen gate to keep unwanted fish from entering at the inlet and pond fish from leaving at the outlet.

Water inlet

All the ponds, except for those filled directly by a spring or by rainwater, need water inlets.
During the construction of inlets, filters should be used in the channel so that the unwanted fish or other materials do not enter into the pond and the water is clean.
A water inlet can be as simple as a bamboo pipe of good diameter running from a water source through the wall into the pond.
The inlet pipe should be placed above the water level.
A wire screen makes a good filter.
The horizontal screen is very effective.
A nylon mesh bag makes a good filter and can be fixed to the inlet pipe.
A sand and gravel filter is also used, but it requires a small tank at the water inlet, it is more effective and economical.
If the water is muddy, or has plenty of leaves or grass in it, the wire screen is better.
If the water source is free from organic material, the mesh bag will work.
If the water contains unwanted fish and more organic matter, sand and gravel filters are best.

Sealing the pond bottom

Leaking Ponds

One of the most common farm pond problems is heavy water loss through leakage. The ability of the pond to retain water depends largely on the characteristics of the soil at the pond site. Most leaky pond problems can and should be prevented by cautious site selection. Before building a pond, be sure to test the capacity of the soil to hold water. Soils with a high clay content will minimize seepage since clay particles tend to swell when wet and, thereby, provide a good bottom seal.

If the soil has more clay in it, no special sealing is needed.
If the bottom is sandy, it should be sealed to hold the water. To seal the bottom a clay core lining is built over the pond bottom.
Another method of sealing the pond bottom is with cement blocks, but it is expensive.
The most commonly used pond sealant is bentonite clay. Bentonite is most effective on sandy soils that contain insufficient amounts of clay. For best results, bentonite should be spread evenly over the dry pond bottom at a rate of 50 lbs/100 ft (20,000 lbs/acre) mixed with the existing soil, moistened, and then compacted with a roller.
Sealing with flexible plastic sheeting of polyethylene, or plastic or vinyl, or butyl or rubber sheet liner at least 2 mm thick is another method of sealing.
The pond liners should be covered by at least 6 inches of sand or fine soil.
Technique developed in the USSR, is called gley or biological plastic. In this method, the pond bottom is covered with animal manure after cleaning the bottom. The animal manure layer is then covered with banana leaves, cut grasses or any vegetable matter, and a layer of soil is put on it. The layers are rammed down very well and 2-3 weeks are allowed to elapse before filling the pond.

Preparation of pond

Preliminary or preparation stage

Soil sampling:

Before starting other procedures, the soil should be tested. Samples are collected from the bottom of the pond and dike. Generally, pH and organic matter contents are analyzed. pH is important to determine the amount of lime to be treated later. Soil sampling is very important, especially for the new ponds.

Demudding:

One of the most important steps of pond preparation is to “de-mud” the pond, which we wish to prepare. “De-mud” basically is the process of removing mud from the pond which we wish to use. The main purpose of demudding is to make it more suitable for fish farming. Demudding can be done just by removing the mud from the pond, which is the easiest way. Instead of demudding directly, we can go for deepening of our pond which is the best option for larger fishes.

Pond drying:

The bottom of the pond is dried to remove the unwanted fish species. Drying is done until the soil cracks. Drying also ensures the oxidization of harmful substances and mineralization of organic matters.

Make the dike of the pond taller:

The most common problem of the rainy season for most of the ponds is that flood can carry away fishes of the pond. So, if the pond is located in an area which is closer to the river or stream, then taller embankment or dike is a must. It should be at least 2 to 3 ft higher than the highest level of water in the pond. This can be done very easily and automatically during the time of digging or demudding. Sand removed during de-mudding/digging can be used to make dikes taller. Otherwise, sandbags can be used to make the dikes/embankments taller.

Efficient inlet and outlet system:

Efficient inlet and outlet system is very much important for the proper working of the pond system. This mostly comes in the form of a pipe through which water can enter and exit from the system. The inlet system of the pond should be placed slightly higher than the outlet system to ensure maximum water flow.

Proper inlet and outlet system prevent overflow of the pond by taking care of heavy rainfall/slight flood. This is very much helpful for the proper maintenance of water quality.

Treatment stage

Controlling harmful aquatic plants and animals:

Aquatic weeds and insects both are very much harmful to fish farming ponds as weeds consume almost all nutrients and reduce the amount of oxygen. Their growth should be controlled efficiently so that they cannot create any problem in the pond.

Removing cannibalistic and unwanted fishes:

Removal of cannibalistic and unwanted fishes is very much important step in pond preparation. Shol, gozar, boal, taki, etc. are cannibalistic fish and mola, dhela, chanda, pumpti etc. are unwanted fish. They can be removed by drying the pond or by using poison in the pond. Rotenone powder is the best option for this purpose.

Conditioning the pond:

Conditioning is done by application of a layer of lime or calcium hydroxide which is spread over the bottom of the pond for two weeks. It is usually applied during or after the pond drying stage. This removes the acidity of the soil, facilitates biogeochemical cycles and prevents unwanted species.

Liming can be done in three different ways:

By broadcast over a dried pond which includes the dike walls.
By mixing with water and spraying over the pond and
By liming the water flowing into the pond.

Manuring:

After 15 days of liming, manuring or fertilization is done in order to facilitate the growth of fish food organisms. Manure can be of organic or chemical nature. The application rate of raw cow dung for stocking pond is 2-3 tonnes/ha. The application rate of poultry manure is 5000 kg/ha. Use of chemical fertilizer depends upon the concentration of phosphorus and nitrogen in the soil and varies accordingly. The standard combination of NPK is 18:10:4 for freshwater ponds.

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