Rescue Earth System

Using Vetiver Grass to Rehabilitate Eroded Landscapes

Vetiver Grass Systems

Vetiver Grass Systems

Restoration of Degraded Landscapes

By following the principles of the Regenerative Design Framework we can use Vetiver Grass Systems to help rehabilitate severely eroded landscapes, especially when used in conjunction with the other ecosystem restoration solutions we promote such as: Leaky Check Dam Systems, Infiltration Swale Systems, Keyline Water Management, etc.

Although Vetiver Grass Systems are not a panacea, they are a key intervention for cost effective ecosystem restoration work. Vetiver grass (Vetiveria zizanioiodes) can be grown over a very wide range of climatic and soil conditions, and if planted correctly, it can be used virtually anywhere under tropical, sub-tropical, and Mediterranean climates.

Soil erosion is one of the greatest threats to our planet. Vetiver Grass Systems can be an important tool to help reduce erosion by up to 99.9% when they are integrated with the other ecosystem restoration solutions.

There are many more positive from outcomes.

Deposition of silt and organic matter from a flood event is evident in this photograph.

Vetiver Grass Properties

The cultivated variety of Vetiveria zizanioides, with its center of origin in southern India, has hydrophytic characteristics, but thrives under upland non-wetland conditions. The very basis of the Vetiver System is that when vetiver grass is planted as a hedgerow across a slope, it forms a very dense barrier that slows down and spreads rainfall runoff.

Then combine this with a very deep and strong root system (average tensile strength of 75 Mpa), a wide range of pH tolerance from about pH3 to pH 11, a high tolerance to most heavy metals, an ability to remove from soil and water large quantities of excess nitrates, phosphates and farm chemicals, and an attribute of sterility and non-invasiveness,

Vetiver grass can be used for soil and water conservation, engineered construction site stabilisation, pollution control (constructed wetlands), and most other uses where soil and water come together. This should be exciting news to those who have to find solutions for improving degrading and polluted soils and water supplies and maintenance of earth based structures.

 

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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