What is needed to construct a SSD?

The types of materials needed to construct a sand dam depend on the type of dam. that is found most suitable at the selected location. This depends on physical properties of the catchment and on the materials available on the market as well as within the area of the selected sand dam location. If materials like stones and sand are locally available, this will reduce costs of materials and transport. The following focusses on stone-masonry dams.

Cross section of a sand dam body and its dimensions

The following construction materials are necessary to build a stone masonry sand dam.
Stilling basin:
1:3 mortar
Large boulders

Dam:
1:4 mortar with well interlocked stones, ratio cement:sand:hardcore = 1:4:9-12
Upstream wall and top of dam plastered with 1:3 mortar (30 mm)

Foundation:
1:3 mortar foundation (100 mm)
1:4 mortar with well interlocked stones, ratio cement:sand:hardcore = 1:4:9-12
(reinforcement bars of barbed wire (400 mm spacing)

Quantities of building material

The quantity of building materials can be calculated from the dimensions of the dam as explained below.

Concrete
The mix ratio for concrete is 1 : a : b.
In which, 1 = cement proportion : a = sand proportion : b = coarse aggregate proportion

If the amount of concrete needed is C, then:
Cement Quantity (kg)= 1 * C * 1400 * 1.3 * 1.05
Sand Quantity (m3)= a * C * 1.3 * 1.15
Gravel Quantity (m3)= b * C * 1.3 * 1.15

Stone Masonry
For water tight structures usually 65% of masonry body is proposed to be stone and 35% cement mortar. So, if the volume of stone masonry work is S, then
Volume of Stone (m3)= 0.65 * S * 1.35
Volume of Mortar, M (m3)= 0.35 * S

If mix ratio of mortar is 1: C,
Cement Quantity (kg)= 1 * M * 1400 * 1.2 * 1.05 (1+C)
Sand Quantity (m3)= C * M * 1.2 * 1.2 (1+C)

Plastering
Follow the same formula used for mortar ingredients of stone masonry.

Pointing
Pointing area is taken as 1/3 of plastering area and then follows the same way used for plastering.

Water
Water required for mixing, curing, washing dirty construction faces, workers construction and food preparation is roughly calculated from the total cement requirement of the site.
If Z Quintals of cement is required to complete the construction work,
Total volume of water (litre)= 280 * Z

Example of a bill of quantity for materials and transportation costs in ETB (2007)