Module 1: Fundamentals of Reservoir and Farm Ponds
Module 2: Basic Design Aspect of Reservoir and Far...
Module 3: Seepage and Stability Analysis of Reserv...
Module 4: Construction of Reservoir and Farm Ponds
Module 5: Economic Analysis of Farm Pond and Reser...
Module 6: Miscellaneous Aspects on Reservoir and F...
Lesson 26 Operation and Maintenance of Water Harvesting System
Many water harvesting projects have failed or experienced serious problems due to lack of an integrated approach during the planning process, especially during implementation, operation and maintenance of the system. Lack of maintenance is a common cause of failure of such schemes. It is often assumed that the beneficiaries will maintain the system once it is executed, but the stakeholders may not have the resources or skills needed to do so. Therefore, the operation and maintenance cost of the project must be taken into account at the planning stage so that the system will continue to function after the completion of the project.
Unfortunately, water harvesting techniques introduced through new projects often ignore indigenous practices prevailing in the project site. Consequently, the local people or the beneficiaries, unfamiliar with the advanced approaches, do not find any scope to be involved in any meaningful participation in planning and implementation process. Thus, where advanced approaches in water harvesting system are to be introduced, it becomes essential to train the local people on construction methods, operation and maintenance of the harvesting structures to ensure smooth and long term functioning of the system.
This chapter focuses on the operation and maintenance of the various water harvesting systems.
26.2 Implementing Water Harvesting Systems
Participation of beneficiaries in the entire process of planning, execution and monitoring of water harvesting projects and most importantly in implementation should be given top priority. It is so because the failure of the project is most likely without their involvement. Any water harvesting systems should possess three virtues in common such as:
It must cater to the needs of its beneficiaries
It should be accepted unanimously by the stakeholders
It should be sustainable and environment friendly.
The suitability of water harvesting system under a set of environmental and geophysical conditions depends upon the factors such as, most importantly, the cropping pattern and the socioeconomic and cultural status of the stakeholders. Besides participation of the people in planning and implementation process, the availability of labour and material for the project, accessibility of the site and distance from villages are the other factors to be taken into active consideration.
A consensus is required on the operation and maintenance aspects of these structures. Involvement of local administration and non-government organizations in implementation of the project plays an effective role through developing a collective responsibility.
Land tenure in rangelands varies from place to place. In some countries, apart from the existence of other forms of land tenure such as rented and private land ownership, the rangeland is largely public land. However, most of the rangeland is private tribal land in some other countries. There the community land is commonly overgrazed and little attention is given to sustainability.
Although rainfall is generally greater in mountainous areas than in the rangelands, these areas are generally less accessible and inhabitated by marginal and poor communities. The complex landscape consists of steep slopes, terraced croplands, sloping rangelands, and scattered patches of shrubs and trees. Most of the agriculture in these areas depends on direct rainfall. Irrigated agriculture takes place along the banks of the ephemeral streams that dissect the mountains. The main cause of land degradation here is due to water erosion.
Considerable progress has been made in identifying efficient water harvesting and water use schemes for both crop production and combating desertification. Constraints to the implementation and adaptation of these schemes include less familiarity of farmers with the technology, conflicts and disputes on water rights, land ownership; and lack of adequate characterization of rainfall, evapotranspiration and soil properties.
Water harvesting may be implemented by a farmer, a community or by public agencies. Micro-catchment water harvesting usually comes within individual farms. This is a simple and low-cost approach; however farmers may experience some difficulty in laying out contour lines required for installation of the structures. Macro-catchment water harvesting systems are to be implemented through a project authorized by the local community with the assistance and guidance from the government bodies. Large scale long slope and/or floodwater harvesting schemes generally need the intervention of public agencies. Such projects usually involve direct intervention of government organizations, machinery and hired labourers. Here the initial cost is relatively high. Moreover, such top-down approaches are rarely successfully. Most of the water harvesting projects implemented by this approach have failed and sometimes abandoned by the beneficiaries.
Projects involving farmers and local communities have been more successful than top-down projects. However, simple demonstrations, training, and extension services are required for effective implementation of such projects. The main advantage of the top-down approach is that it is quick and efficient in rehabilitating the degraded land. However, as noted earlier, the costs are high and large systems require expensive repairs that are beyond the resources of local people. It can be justified in areas with high rainfall, where less labour is available and a quick result is needed.
As a first step, all parties (farmers, community, authority, and government representatives) involved with the project should be engaged in a round-table-discussion to identify the best technical approaches for the locality. The plan of action developed should be simple enough for the people to implement. Furthermore, the water harvesting system itself must be sustainable. The planner should be ready to listen and learn from the farmers. Sharing farmers views in the managerial role contributes to the success of the project.
26. 3 Considerations in Implementation
Water harvesting projects implemented without a complete integrated study prior to execution have been subjected to many technical errors in design and implementation. In many cases the techniques applied are inappropriate and do not meet the requirements of local conditions. Sometimes with appropriate techniques the installation process is observed to be inadequate or incomplete.
Some basic technical criteria that must be fulfilled while implementing water harvesting projects are:
Slope: The engineering structures required in a given situation increases as the slope increases. But, water harvesting is not recommended for the areas having slope steeper than 50% as it may not be economically viable.
Soils: The soil should be deep, neither saline nor sodic, and should be generally fertile. The major limitations are with limited soil depth and sandy soils which have a relatively high infiltration rate and low water holding capacity
Costs: The cost of a water harvesting project depends upon the amount of earth/stonework involved. Even when this is directly carried out by farmers, it should be considered as a standard for labour requirement to construct a system. Thus, the selected technique would become suitable to the farmers' affordability.
Other issues that must be addressed while implementing the water harvesting projects are reduction of maintenance and overall project cost. Some of them are discussed in the following section.
26.3.1 Over-Design and Under-Design Issues
Over-designing or under-designing may lead to the failure of the project. Overdesign increases project and maintenance costs which may result in abandonment of the project before its implementation. Although water harvesting has been practiced in some parts of the world for centuries, no such specific general rule or guideline is available on design issues except some limited design data. Even when the design data is available at a location, it lacks the ability to be transferred from one location to the other because of constraints imposed by local conditions.
The impacts of climate change across the globe such as longer dry spells and higher rainstorm intensities may require higher catchment; cropping area ratios and more solid (higher, broader and more compacted) earthen structures.
26.4 Operating Water Harvesting Systems
At the beginning of the project, a locally acceptable team involving mainly the project beneficiaries should be constituted to oversee the operation of the water harvesting system. The responsibility of this body should extend beyond the project phase. Guidelines and procedures for the operation and maintenance of all components of the water harvesting system should be developed for the earthen dikes and bunds, water storage structures, spillways, and diversion structures. Micro-catchment water harvesting systems should be inspected after every runoff-producing rainstorm so that any minor breaks in bunds can be promptly repaired.
For large scale flood water harvesting system there may be a need to create a local association to liaise with the government agency on issues pertaining to the project. This local institution may be supported by the government for a limited period of time and thereafter the association is expected to take over the full responsibility of operating and maintaining the project. All new water harvesting systems should be inspected often especially during the first one or two rainy seasons following construction. Treated catchment should be protected against damage by grazing animals. Silt and trash should be removed from the water conveyance and distribution systems and other storage facilities.
26.5 Maintaining Water Harvesting Systems
In many cases, it is observed that the operation and maintenance of water harvesting projects are not handed over to the beneficiaries instead the government agencies look after it. Maintenance of a water harvesting system requires daily observation to assess the effects of heavy rainfall, damage by animals, etc., and this is unlikely to be achieved when the responsibility lies in the hands of a government agency. Hence, it is necessary to hand over the responsibility of maintenance of the project to all the stakeholders. They should be made aware of the importance of regular maintenance for the long-term functioning of the system. In addition, they must contribute to ensure that such maintenance is conducted promptly and effectively.
26.6 Monitoring and Evaluation
Monitoring and evaluation of a project is essential to assess its performance, the extent to which it is meeting the design specifications, or the degree and causes of its success or failure. But it is rarely seen in case of water harvesting projects. However, monitoring and evaluation of water harvesting projects are essential to allow the operators to take remedial measures in time and ensure the effective operation of the project. For example, if it is monitored that the amount of runoff water has been overestimated, then the cropped area can be reduced to achieve the desired results. Further, the information gathered also enables all stakeholders to learn about the mistakes in approaches and creates scope for necessary modification or improvement in the future projects. This is a kind of rectification of errors in earlier approaches. Without monitoring, the mistakes get repeated in subsequent projects and the system does not improve.
Data pertaining to all aspects of the functioning of a project including technical performance of the structures, agricultural performance, environmental factors (rainfall, soil erosion, etc.); and socioeconomic and cultural impacts need to be collected. For large projects using advanced technology like GIS, care must be taken while selecting monitoring sites along with ground truthing to enable one to obtain up to date information on the project evolution.
For orderliness in the collection and dissemination of water harvesting information, government agencies can be assigned with the responsibility of collecting, analyzing and storing data regularly from both ongoing and completed projects. For instance, following the failure of a project for some avoidable reasons, a team conducted a survey on monitoring and evaluation aspects of the collapsed project using a set of questionnaires. The response of the beneficiaries indicated that the issue of land tenure was the major attributable criterion for failure of the project. This problem could have been detected and avoided if a systematic monitoring and evaluation approach would have been carried out at the planning stage of the project.
Apart from the above, the project planners should ensure that all comprehensive reports of various phases of the project are kept protected. These reports can be used later for several purposes such as:
means of evaluating the degree of realization of the project objectives
to determine the accuracy of the project design assumptions and address any errors
source of information for planners and government establishments to plan the development need of the region; and
to evaluate the response of the local populace to the new system.
26.7 Extension and Training
Extension and training are some important steps for the success of a project. Training programmes need to be organised on the techniques used in a water harvesting project for the beneficiaries and field level extension workers. These programmes should run concurrently with the project implementation through project activities for practical demonstrations. In other words, such training programmes help in bringing together the project staff, extension agents, farmers, and pastoralists across the table and make them understand their responsibilities and complementary roles for the success of the project.
Keywords: Operation, Maintenance, Over-Design, Under-Design
Owesis, T. Y., Prinz, D. and Hachum, A. Y. (2012). Rainwater harvesting for agricultural watersheds in the dry areas. CRC Press publication.