**How much water is in my dam?**

**MOISTURE CONTENT ON DELIVERY**

Grain is seldom sold at the standard moisture

content. When the moisture content is greater than

the standard, the weight of the grain is discounted

to make provision for the additional moisture.

The following moisture content standards are used

as condition for the delivery of commodities at

silos:

**Delivered Agreed standard**

Sorghum

Wheat

Maize

Soybeans

Sunflower

Groundnuts

Canola

Barley

Oats

**For example: Maize is delivered at a**

**moisture content of 14%.**

**Formula:**

(100% - delivery %)

(100% - standard %)

= (100% - 14%)

(100% - 12,5%)

86%

= 87,5%

= 0,9828

By multiplying the weight of the grain

delivered by 0,9828, the weight of the

maize is calculated at a moisture content

of 12,5%, for example the weight of a

load of maize of 32 000 kg delivered at

14% moisture is (32 000 kg x 0,9828)

31 449,6 kg @ 12,5% moisture content.

≤ 14% 12,5% – dry

≤ 13%

≤ 14% 12,5% – dry

≤ 13% 12% – dry

≤ 10% 9% – dry

≤ 7%

≤ 8%

≤ 13%

≤ 13%

There are a few measurements that you need:

Surface area

Maximum depth

**Surface area**

The surface area of a dam is calculated by

multiplying the length by the width.

This will be the case for square or rectangular dams.

Most dams start out as a square or rectangle, but

over time appear to become rounded. If the dam

is not exactly square, round the measurements off.

Make sure to err on the conservative side.

Dams such as Turkey Nest dams (used to store

water on a relatively flat terrain) can be any shape,

and their dimensions may need to be approximated

to calculate the surface area.

Gully dams (used to store water in a gully) can also

be of varying shapes and the formula for calculating

their storage capacity is discussed later.

**Volume**

With the surface area depth calculated, the volume can then be determined:

(Where 0,4 accounts for the batter slope on the sides of the dam)

Turkey Nest dam

Gully dam

**Example: 30 metres x 50 metres = 1 500 m**

**2**

**Volume (m**

**3**

**) = Surface Area (m**

**2**

**) x Max depth (m) x 0,4**

**8**

**7**

**Relevant**