Aqua-business con: How to calculate seepage and evaporation

Last time we saw on how to estimate amount of water required in a fish pond, today we shall see on how to calculate and prevent seepage and evaporation.

Fish pond like any other water bodies tend to be affected by seepage and evaporation ,but few fish farmers consider this an important issue and most of the time they think fish farming is an weekend job forget important parameter to check and control frequently.

Seepage is the slow escape of a liquid through small holes. In fish pond water losses through filtration by dyke or bottom of the pond.

Evaporation is the process by which water changes from a liquid to gas/vapor.

Calculation of seepage and evaporation have become crucial due to it is effect on the stability of the ponds. One of the main factor that lead to the decrease of water in ponds.

A farmer should note that, a new pond has higher level of seepage problem than that of the old pond. Hence a farmer is advised to be care in constructing fish ponds include materials used in constructing and type of soil forexample sand soil has higher seepage than clay soil.

In some area, farmer will be forced to remove the soil available in that area and replace it with good soil from another place. A good construction of a pond will ensure a long lasting of a fish ponds otherwise it will course loss to the farmer.

In calculating seepage the following formula is used:

Seepage water (m³/day) = seepage losses (m/day) x surface area of the pond (m²⁾

Example: Consider a fish pond with 100 m² with a seepage level of 4 mm/day. Required to calculate amount of water losses in fish pond.

Note: Information concerning seepage level can be obtained from meteorological station and normally evaporation ranges from 2 to 7 mm/day.

Solution

Fish pond size = 100 m²

Seepage level = 4 mm/day change into meter = 0.004 m

Then

0.004 m/ 100 m² = 0.4 m³

But

1 m³= 1000 L, hence 0.4 m³= 400 L

Therefore, 400 L will be lost from a 100 m²of a fish pond.