Dry Stone Check Dams

Dry Stone Check Dams

They are transverse structures built without mortar. They are built in small toys in places that do not carry much water. Dry wall sills are generally used for the reclamation of creeks (flood fissure, flood drains), the water collection basin of which is smaller than 100 hectares. If there are plenty of intact stones in the vicinity of the stream to be rehabilitated, it is appropriate to rehabilitate the flood crevices and creeks with dry wall sills. The presence of the stones to be used in the locality is important due to the cost. In the absence of stones in the region, other methods such as lattice wire threshold, which are more economical, should be considered. Dry wall sills are usually made with a height of 0.70 - 2.00 meters. The depth of the foundation and the height of the wings are not included in the height of the structure. It is not recommended to make thresholds higher than 2 m. Dry wall sills are sized according to the size of stream basins and crevices.

A dry stone check dam is a structure built using dry stone masonry, typically in areas with little to no mortar, to control water flow, prevent erosion, and store water temporarily. These dams are often constructed in arid or semi-arid regions where water scarcity is an issue, and they help to manage water resources by reducing the speed and volume of flowing water. They are typically used in small-scale water management systems, such as in small streams or wadis (dry riverbeds that fill with water during heavy rains).

Purpose of Dry Stone Check Dams

1. Erosion Control: Dry stone check dams slow down the velocity of flowing water, preventing soil erosion and the washing away of valuable topsoil.

2. Water Storage: They temporarily store water during rainfall or floods, allowing it to seep into the ground, replenishing groundwater tables.

3. Flood Control: By reducing the speed and volume of water flow, these dams help to mitigate flood damage by dispersing water over a longer period.

4. Sediment Control: Check dams can trap sediments carried by water, improving water quality downstream by preventing siltation of rivers and reservoirs.

5. Recharge Groundwater: The water stored behind these check dams slowly infiltrates the soil, helping to recharge groundwater levels, which is especially useful in dry regions.

Construction Method

1. Selection of Site: The site is chosen in a stream or small river where water flow is not too intense. It's essential to select a location where the dam can effectively slow water flow without being damaged by strong floods.

2. Dry Stone Masonry: Stones are stacked without the use of mortar, creating a stable structure. The interlocking stones rely on gravity and the friction between them to hold the dam in place. The construction technique requires skill to ensure the stones fit together tightly to prevent leakage.

3. Structural Design: The dam is designed with a sloping face to direct the water flow downward. The upstream face may have larger stones to absorb the force of the water, while the downstream face is more gently sloped.

4. Maintenance: Dry stone check dams are relatively low-maintenance because they don't use mortar that might erode. However, periodic inspection is necessary to ensure that no stones have shifted or caused cracks that could allow water to seep through.

Benefits of Dry Stone Check Dams

1. Environmentally Friendly: They are an eco-friendly alternative to traditional dams, as they use local materials and do not require cement or heavy machinery, reducing environmental impact.

2. Sustainable Water Management: In regions where water is scarce, these check dams provide a sustainable method for water retention and groundwater recharge without relying on large-scale infrastructure.

3. Low-Cost Construction: Dry stone check dams are relatively inexpensive to build compared to other forms of dams. Since they don’t require mortar or complex machinery, they are cost-effective, especially in rural or developing areas.

4. Versatility: These structures can be used in a variety of landscapes and terrains, from mountainous regions to flat lands, as long as the water flow is manageable.

5. Cultural and Aesthetic Value: In some regions, dry stone structures are part of cultural heritage. The construction method also blends well with natural landscapes, providing an aesthetically pleasing solution to water management challenges.

Challenges

1. Durability: While dry stone check dams are quite durable, they are still subject to wear from extreme water flow or seismic activity. Maintenance and occasional reconstruction may be necessary after heavy rains or floods.

2. Size Limitations: These check dams are typically small and not suitable for large rivers or extreme flood conditions, where reinforced concrete dams or other larger structures might be necessary.

3. Construction Skills: Building a dry stone check dam requires skilled labor to properly fit and place the stones, ensuring that the dam will hold together and withstand the water pressure.

Conclusion

Dry stone check dams are an effective, low-cost, and environmentally friendly method of water management, particularly in areas where water conservation is essential. Their ability to control erosion, store water, and recharge groundwater makes them valuable in arid and semi-arid regions. By using locally available materials and minimizing the need for modern construction techniques, dry stone check dams offer a sustainable solution for small-scale water management.