Rescue Earth System
Leaky Check Dams
Leaky Check Dam Systems are the best way to slow water flow and help restore the ecological function of degraded water courses. They also help to reduce peak water flow in watersheds and thus help to mitigate flooding.
Leaky Check Dam Systems
Leaky Check Dam Systems are used in the regenerative restoration of degraded landscapes as a natural flood management and erosion control measure. They are small leaky barriers constructed across a swale, drainage ditch, erosion gully, or waterway to counteract erosion and downstream flooding by reducing water flow velocity. Only natural materials are used.
A natural looking ‘fallen log’ Leaky Check Dam is aesthetically appealing, low cost and very effective.
Leaky Check Dams
Most of the Leaky Check Dam Systems (LCDS) in the Rescue Earth System use stone and wood (logs and layered branches, willow weaving, etc.) as their main structural element and are built using volunteers.
Using LCDS as Natural Flood Management
Natural flood management involves implementing measures to:
- restore or mimic natural functions of rivers, floodplains and the wider catchment using Ecosystem Restoration
- temporarily store excess water in the landscape, either in the river or in the flood plain by building Leaky Check Dam Systems to slow water flow
- intercept rainfall to prevent it from reaching the river in the first place by increasing the infiltration of water into the soil such as in Infiltration Swale Systems and Rain Garden LID Systems.
- slow the rate at which water runs off the land into rivers by using Keyline Water Management, Regenerative Grazing Management and Regenerative Food System.
Diversion of water into Infiltration Swale Systems and into constructed wetlands is a key element in the revitalization of micro-environments and the rehydration of the landscape.
A natural yet more constructed Leaky Check Dam is still low cost and very effective.
Using LCDS to Increase Ecosystem Function
The area surrounding the leaky check dams and sand check dams have many benefits including better quality of water to life behind the barrier, prevention of soil erosion, available nutrients for wildlife, stabilisation of river banks, spawning ground for aquatic life, rooting habitat, place of nesting birds, areas of growth for microbes, algae and fungi, efficient temporary storage of water and a slow release of water into surrounding area. There are also many other benefits to the local ecology.
A natural looking rock Leaky Check Dam in a stream bed — showing a variety of native woody and herbaceous plant species provide habitat and food for aquatic organisms, as well as terrestrial animals.
Using LCDS to Repair Gully Erosion
Leaky Check Dams are a low-cost and low-risk erosion control method that that is found throughout the world. Arresting and reversing gully erosion requires resting the area from grazing animals and taking steps to rebuild and re-vegetate gullies. Leaky Check Dams are one of the most simple and cost-efficient methods to help slow water flow and start rebuilding gully floors.
A rock Leaky Check Dam is often the best option to repair erosion gullys.
Using semi-LCDS as a Water Source in Arid Regions
Sand check dams provide a sustainable solution for water-scarce regions as climate change kicks in. They are easy to build and maintain, and last for decades. They provide water, particularly in arid regions, for people of all income levels — but are particularly beneficial to low-income, disadvantaged households and women.
Sand dams are a low-cost investment infrastructure built in close collaboration with communities. There is no sophisticated technology involved, except for pump installations. The dams can last for more than 100 years without major refurbishment.
Sand Check Dams
Sand check dams are a low cost, durable solution to the age old problem of water scarcity in arid and semi-arid regions. They have huge potential to kick start development whilst safeguarding precious water resources for future generations. They maybe built anywhere that the 4 pre-conditions are met: (1) a seasonal river with (2) a sufficient sandy river sediment, (3) a suitable accessible foundation and (4) a sufficiently impermeable riverbed. However the choice of site has a huge impact on the cost-benefits of a dam.
The sand check dams help communities adapt to climate change by ensuring water availability throughout the year for both people and livestock. Proposed income-generating activities in this project include the establishment of gardens, nurseries, orchards, and fisheries. Furthermore, sand dams reduce time needed for community members to collect water, which they can then spend either doing schoolwork or income-generating activities. The dams are thus particularly beneficial to poverty-stricken communities, and will also help to ensure food security.
Sand check dams are implemented across and into seasonal sandy riverbeds in order to capture and store water beneath sand. In addition to this, groundwater recharge occurs upstream of the sand dam. The first requirement for implementing sand dams is the existence of a seasonal river with sufficient and accessible sandy sediment and bedrock in the river-bed.
Sand check dams provide a sustainable water source, and conserve ecosystems by raising the water table around them. Natural vegetation and biodiversity dependent on aquatic ecosystems near the sand dams also benefit.
Riparian Zones are Restored by Reduced Peak Flow
Riparian zones are the transitional areas between land and water, including the margins of streams, rivers, lakes, and wetlands. They are rich in biodiversity and play an important role in protecting water quality and stream ecosystem health.
Riparian zones containing of a variety of native woody and herbaceous plant species provide habitat and food for aquatic organisms, as well as terrestrial animals. Root structure in a healthy, dense mix of riparian vegetation fortifies streambanks, which helps control erosion caused by extreme flow velocities and flooding.
Riparian vegetation functions as a large sponge that reduces overland surface flow and absorbs pollutants caught up in stormwater runoff. In addition, tree canopy in riparian zones provides shade, which helps maintain cooler water temperatures and higher dissolved oxygen levels.
Although riparian zones begin at the water’s edge, there are no formulas or rules that clearly define the outer limit. However, research shows that many of the benefits provided to streams by healthy riparian vegetation are retained with a 35-foot buffer (Wenger 1999). These benefits increase considerably with a 100-foot buffer and even more so with a 300-foot buffer.
Considering all the benefits that healthy, natural riparian zones provide to streams and other surface waters, these areas should be protected. However, properties are often developed without knowledge or consideration of the importance of the riparian zone.
During the development process, riparian areas are degraded when vegetation is removed, the terrain is graded or plowed, utilities are installed, structures are built, and areas are paved.
Changes to the landscape and subsequent human activity in the riparian zone have consequences on steam ecosystem health; nutrients from fertilizers and pet wastes, contaminants from cars and roads, and soils from eroded areas are among some of the pollutants that wash into and degrade streams and other surface waters.
A really good example of a degraded yet healthy forested riparian zone — reducing the peak flow rate will increase the sedimentation and plant diversity on the waters edge.
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We must rise and face the environmental challenges of our time by reversing the economic, physical and social decline of places. This can be achieved by the practice of regenerative restoration of degraded, damaged, or destroyed ecosystems and habitats in the environment by active human intervention and action.
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