«Report of Kenya visit Goal of the visit Review of Watershed Management Plan of the Muvitha Kathemboni watershed Table of content Summary Places and ...»
Global Ecology Institute
Report of Kenya visit
Goal of the visit
Review of Watershed Management Plan of the Muvitha Kathemboni watershed
Table of content
Places and issues assessed during the Kitui visit
Sustainable Water Management as the basis for rural and urban plannin
Description of ecological and hydrological situation of the watershed
Proposal for long term engagement, models and regenerative water management
Education programs for sustainable and community based infrastructure and land use Links Photos Summary The current land-use within the catchment of the Musosya dam has lead to a full siltation of the dam over the last 10 years. This means that the local population currently does not have access to water from the dam. The first step that has to be taken is to change the land-use. We recommend to form a watershed community involving all stakeholders. In each parts of the catchment different measures have to be taken for restoring the catchment. As a general line we recommend to increase vegetation cover so that all earth is covered and rooted. To achieve this we propose a common livestock grazing management. In addition mainly small earth works should be undertaken, which are already widely known by the community members.
On the slopes the natural bushland/forest vegetation should be restored. We propose to build an open well in the silted dam to get water accesses. Furthermore other wells should be constructed in the valleys for decentralized access to water.
Reservoir in Kitui Town Places and issues assessed during the Kitui visit 31.08.2013 Kitui Town Arrival in Kitui town Study of Rainwater Harvesting techniques and agriculture practices Visit of earth dam near Kitui town Piped and hand fetched (potable) water supply of Kitui town 01.09.2013 Kitui Town Study of rainwater harvesting techniques and agriculture practices Waste water infrastructure of Kitui town Dried up riverbeds around Kitui town Visit of unfinished building site of concrete dam 02.09.2013 Kitui Town, Nthongoni, Kitui County Field trip to Muvitha Kathemboni Watershed Assessment of silted Musosya earth dam Study of earth work like terraces and swales 03.09.2013 Nthongoni, Kitui County Determination of watershed size Erosion on roads Influence of animal traffic and grazing Study of grassland vegetation, Insecure agriculture production due to regular floods Deforestation 04.09.2013 Kitui town Review field visits Mapping of watershed Vegetation cover, mulch, grazing, maps 05.09.2013 Nthongoni, Kitui County Sand Dam Wells Upper Catchment 06.09.2013 Nthongoni, Kitui County, Kitui town Retention ponds along road site Meeting with watershed community members Sustainable Water Management as the basis for rural and urban planning Introduction to the principles of a Water Retention Landscape Desertification, droughts and floods have a common reason: the damage of the hydrological balance by deforestation, industrial agriculture and sealed surfaces in urban areas. Naked soil becomes hot and looses the ability to absorb water. Rain erodes the topsoil. The earth body dries out, global groundwater reserves and soil fertility decreases. For food sovereignty we need a proper water balance.
A Water Retention Landscape is a model for natural and decentralized water management and restoration of damaged ecosystems. It is a basis for reforestation, horticulture and agriculture in regions threatened by desertification, and is part of a comprehensive model for sustainability on a large scale including water, food, energy and community building.
In short the basic principles of the Water Retention Landscape are:
No rainwater should run over the earth surface but rather be infiltrated into the soil where it falls. Taking a certain territory into the focus the goal would be that no more rainwater and waste water leaves the territory but rather all water flowing away comes from springs.
If the aquifer is recharged water is available from springs and from wells in sufficient quantities for all human usage. In most cases the soil and the earth body is not capable to infiltrate the rainwater immediately due to mismanagement. Therefore different methods are applied within the Water Retention Landscape to restore the water balance. This includes: building of retention reservoirs (ponds, earth and sand dams), terraces, low proportion of sealed surfaces, road water infiltration, swales, permanent vegetation cover, mulching, adequate grazing management, afforestation… If the principles are understood and integrated in the planning and management, water is available all through the year, erosion is stopped, landslides are avoided, vegetation grows vigorously, rivers are constantly flowing, floods are moderate, risk of fire is low, decentralized biological agricultures enables local food security… Therefore we stress the importance of sustainable water management. In countries which have a low development of infrastructure there is a large potential to implement it in the right manner and not repeating the mistakes of the past and current management.
A detailed description of the Water Retention Landscape is published in the brochure “The Secret of Water” by Bernd Walter Mueller:
http://www.tamera.org/fileadmin/PDF/2.2_The_Secret_of_Water.pdf Description of ecological and hydrological situation of the watershed The Muvitha Kathemboni Watershed area is a typical site in the western part of the Kitui Province.
The catchment has a size of approx 300 ha; the upper part is situated on a plateau on around 1140 mamsl, while the dam is situated at around 1010 mamsl. The flat plateau area is mainly used for agriculture and grazing around the family settlements.
At the edge of the plateau steep to medium steep slopes descend which are mainly stocked with natural trees and bushes. Also some terraced parts occur and most of this bushland is grazed. In the lower parts of the catchment the inclination is softer and much land is terraced for agriculture use. Here houses of the landowners, infrastructure for livestock and grazing areas are situated.
There is access from a larger public road to the plateau area, and a smaller earth road leads to the dam area. A partly very steep earth road runs downhill from the plateau to the dam area.
All land is in private ownership, except the dam area which is public. There are around 30 private owned territories in the watershed area.
The annual rainfall for the area is not precisely known, values range from 300mm/y.
The map shows a satellite image of the area with estimated watershed borders (page 7).
The area shows serious degradation of vegetation and soil. Everywhere erosion occurs as a result of heavy rainwater runoff. Small and large gullies have formed and the eroded material has silted the dam within the short period of 10 years. The vegetation cover of the soil is very little, often the ground is bare. The missing anchoring roots and the compacted soils lead to low infiltration and massive runoff.
The main factors for this ongoing degradation process can be summarized by:
Low vegetation cover and low soil vitality
The main interlinked factors of the land-use techniques are:
Low vegetation cover on agriculture terraces (during dry season) Unmanaged grazing, animal trampling Deforestation for charcoal production, clay brick production and domestic use All of these land-use methods lead to high erosion Low infiltration leads to high runoff Unstable soil conditions by lack of vegetation and roots Roads and pathways produce high runoff… Compacted soils (livestock) Gullies Siltation of dam Therefore the goal should be the full restoration of the catchment area. Soil and water conservation must work hand in hand to stop the process of degradation and lead to a regenerative state of the catchment.
Satellite picture from Google earth showing estimated catchment border (orange), Main valley and dam (blue) and roads (black) Sample showing the watershed area from topographic map, Kenya Survey Landscape restoration We emphasize that the main goal is landscape restoration for the whole catchment to secure water supply and livelihood from agriculture and other natural resources. This can only be achieved if all owners participate in a watershed management committee.
We propose to formulate goals on which the landowners communally agree, like:
Zero runoff of rainwater (full infiltration of rainwater to recharge the aquifer) Permanent vegetation covers of the soil Permanent running watercourses in main valley Decentralized drinking water access: Wells close to the valleys and the settlements To restore the dam reservoir (by removing the silted material) before avoiding further erosion is not sustainable. The general proposal is to redirect the work and training to the other proposed measures.
In addition we want to emphasize some points that have not been addressed in accordance to their significance. This is the role of vegetation cover, livestock management and the maintenance and use of roads and pathways for a full infiltration and recharge of the aquifer.
During the field visits of the consultation we reviewed the proposed measures for soil and water conservation, mainly aiming in the prevention of erosion.
Recharge of aquifer With regard to hydrology the main goal of the restoration of the watershed is the recharge of the (upper) aquifer. The rainwater is retained (not stored) in the soil and rock of the whole catchment area. After a period of water saturating the upper soil layers and first rock layers the aquifer will refill. This allows extraction of water all the year through from wells in a depth of around 2 -5 meters. Plant and tree growth is prolonged over the dry periods and irrigation becomes possible.
Retaining water in earth dams or sand dams are good means if the soil and earth body can not hold the water during the restoration phase. In the long run the largest and best retention space is the soil and the different layers of the aquifer. The now dried out water flows and river will start to flow permanently again if the soil is recharged with rainwater.
A large part of the area shows very little vegetation and/or leaf cover (living or dead mulch). Farming on terraces without cover crops as well as terrace or bench slopes without vegetation is one reason. Another is a continuous deforestation for fuel uses.
Livestock is probably the strongest factor. Grazing of animals as well as trampling an access paths to water sources with animals result in many areas with bare ground. A sustainable livestock management seems to be the key to a successful restoration.
Livestock management The watershed needs a grazing management plan. This should include the areas for grazing, either privately or communally. Especially the roads and pathways to the settlements and the water sources should be carefully designed. The main access road show strong influence of animal trampling which results in bare and compacted soil. This leads to further erosion and destruction of the terraced land. The steep slopes should be managed to allow natural vegetation growth. Grazing rhythms which support the natural dynamic of this bush and grassland may be applied. Heavy and unmanaged grazing without rotation leads to high runoff which the lower part of the catchment can not cope with.
There are numerous grazing management approaches known in eastern Africa.
We strongly recommend taking local consultation and training for the involved landowners.
Smaller structures Different methods are proposed and already applied in the project. Farmers are trained in terracing, infiltration ditches (swales), stone berms… All this solutions are suitable to infiltrate water thereby reduce runoff and erosion.
And these methods are already applied and culturally accepted in the area.
Nevertheless they can only be of sustainable value if combined with permanent vegetation cover.
Roads and pathways These features need special attendance. They are compacted and act as drainage and runoff channel. Especially the larger access road (see map page 7) must be repaired and regular cutoff drains must be established and the water can be redirected into swales on contour. The water from the roads pathway can act as a rainwater harvesting source, for example irrigation of trees or bananas in pits (see picture below). Most of these works can be done by hand, nevertheless if machinery will be part of the later implementation in the project some repair work of the roads could be effectively done by a caterpillar.
Sidewise (diagonal) direction of water on roads to cut of trenches or swales Check dams For the restoration of the gullies check dams are identified as the right measure. It is necessary to start with small structures where the force of the water is small. Stones, or brush berms or living cuttings of trees/bushes, help to anchor the soil.
Larger check dams can be built in the lower parts of the catchment and stop the continuous siltation of the dam reservoir. Nevertheless a serious of small structures will help to stop the erosion where it starts and thereby help to infiltrate the water on a higher altitude. The smaller the amount of runoff which reaches the downhill part, the lower is the force of the water and the simpler the structures can be.
For example: A check dam build in one of the main gullies close to the dam reservoir, must be build from concrete or gabions. Once the erosion is stopped upstream/upslope also these structures can be built from stone, plant material or from earth.
In some places the construction of check dams in the way a sand dam is build can be useful.
Sand dams Sand dams are constructed within the area to store water in a sand aquifer that forms behind a concrete wall in a riverbed or gully. Hereby we can combine restoration and access to drinking water. Integrating concrete rings (or plastic pipes) before the process of siltation can allow access to water from a well kind of take off and in addition monitor the status of the upper aquifer.