Thursday Nov 14, 2024
Thursday Nov 14, 2024
Wednesday, 14 December 2016 00:01 - - {{hitsCtrl.values.hits}}
Small hydropower plants have contributed to the development of the country without being a burden to the Government
A seminar was held on 6 December organised by Biodiversity Sri Lanka, an environmental organisation and the Central Environment Authority along with members of the Small Hydropower Developers’ Association regarding ecological issues and the future of the small hydro-power industry. The seminar was held in the background of restricted granting of approvals for small hydro-power projects during the past few years and the concerns of stakeholders of the future development of the industry.
Background
The Government develops the large hydro-power projects in the country, while projects less than 10MW capacity are allowed to be developed by the private sector. Local companies investigate possible locations, get acceptance, construct, install power plants and 
the produced power is sold to CEB.
The first small power plant came into stream in 1993 and currently nearly 150 plants are in operation. Small hydro projects are implemented by private developers; getting acceptance and approval for a small hydropower project involves extensive investigations and going through masses of red tape could be a long-drawn-out process.
Structure of a small power plant
The power of water flowing down a stream or a river is used for the generation of hydro-electricity. The quantum of power generated depends on the quantity of water flow and the height difference between the collection point and the generator location. Thus streams in heavy rainfall regions, with high ground level variations over short distances (steep slopes) are suited for power plants.
The water in the stream is diverted by a small dam; generally referred as weir, into a concrete channel of mild slope. At the end of the channel, water enters the penstock generally of steel, conveys water under pressure to the turbine generating power. After power generation, water is returned back to the stream.
High dams store water for major power projects, but in mini-hydros storage is disallowed. The dam is incorporated with a permanently open outlet, allowing a pre-determined minimum water flow to fulfil needs of down-stream users as domestic and agriculture, survival of fish living in the stream and drinking water requirements of animals.
Environmentalist’s point of view
During the Cretaceous Period, around 100 million years ago before separation of earth plates, Sri Lanka, India, Madagascar, South Africa and Australia were bound together and had common animal and plant species. The separation isolated our island to a unique biodiversity rich hot spot. The country also possesses highly varied soil types allowing diverse plant species.
Hydraulic civilisation in the dry zone and clearing of land for agriculture resulted in loss of species, similarly in highlands under plantation industries. But isolated highlands still host some unique species. Among them are 53 varieties of fish, 31 types of frogs, crabs, birds, reptiles based on availability of water and plants that have adapted to the modified landscape.
Of 53 native fish species, 41 are endemic to Sri Lanka and 34 of them are found only in hill streams. Twelve species are critically endangered and 14 are either threatened or vulnerable according to the IUCN Red Data Book.
Environmentalists claim that construction of small hydro-power plants, especially in the upcountry, inundates forests and erode river banks. When they divert water for power generation it creates kilometres of dry sections in the river, affecting fish. In addition, some species of fish travel upstream during the breading season and the erection of weirs across the streams prevents their movement. The diversion of water affects local inhabitants by depriving water for drinking, washing, bathing and aesthetic beauty of waterfalls and affects tourism.
Lost stream stretches may create habitats for mosquitos, vanish bathing pools, alter quality, emit greenhouse gases, promote toxigenic algae and affect the livelihood of humans.
According to environmentalists the channel transporting water from weir to power-house, a concrete structure, obstructs elephants and animals crossing to water-holes in the stream. Also, the construction of power plants lead to pollution, over-exploitation of resources, habitat conversions and sedimentation due to soil erosion results in invasive alien plants threatening eco-systems.
Small Power Producers’ reply
Small Power Producers (SPP), while agreeing with some of the unfortunate effects on the environment, point out that most of the happenings mentioned above occurred long before they entered the picture and they cannot be held responsible. In the construction of major dams, inundation of large extents of lands and forests, drying up of streams below and movement of fish and other species were disregarded as major dams and water diversions help the populace and farmers for cultivations.
According to SPPs most of their dams (weirs) are low and use run of the water without storage. The diversion of water is confined only from weir to power-house and thereafter water is returned to the original stream. No chemicals are added to water during the process. The length of diversion is generally between 500m to 1.5km and the longest diversion is 5km; reduced water affects only this section. Also, the section from weir to power-house is the steepest section of the stream that enables power generation and the very geographical situation does not permit heavy population, thus the affect to local population is low.
The approval process requires the developer to release a specified minimum quantity of water for fish and down-stream users generally referred to as E-flow.
Most weir heights are less than 3m, result only in limited inundation above the weir and do not involve clearing of forests. Average land requirement for a small hydro-power plant is estimated around one Ha. Weir allows nearly 80% of water to be diverted and balance water continue to provide user requirements below the weir. In the E-flow outlet control devises are not allowed, ensuring uninterrupted flow irrespective of weather conditions. But there had been complaints of deliberate obstruction to water flow especially during dry periods and the E-flow outlet being blocked due to sedimentation.
In development of small hydropower projects, the developers are forced to improve local roads, as they too require access to transport their construction machinery and power-house equipment. They also employ locals in construction and in the running of the completed plants, thereby contributing to local economy.
The restrictions placed on approval of small hydro-power projects had its beneficial side too. With the local restrictions some producers were forced to look outside and have been successful in carrying out overseas projects as in Kenya and Uganda.
Extent of development
Mini hydropower plants have already developed in the following rivers:
Role of Central Environment Authority (CEA)
The CEA staff who were present as facilitators for the conference took pains to bring two sides with conflicting interests to achieve a win-win situation without undue strains, for the continuity of the industry, especially considering the massive foreign exchange savings and environmentally friendly endeavour.
Sri Lanka records over 800 waterfalls, of them over 500 are gazetted for conservation and are not allowed for development.
E-flows
Construction of weirs deprive water to downstream users over the affected length until water is returned to the stream, and the amount of extraction could go as high as 90%. Loss of water exposes the stream bed, stops fish movement, affects waterfalls and changes stream habits. The effects could be minimised by continuing a quantum of water, referred to as E-flow.
In approval of projects minimum E-flow requirement for the project is agreed. Generally, basic flow is considered as 300 l/sec and for bathing 1000 l/sec. In addition, to allow movement of fish upstream for breeding purposes, fish ladders need to be provided.
Fish ladders
During the breeding season some fish travel upstream for breeding and large dams have prevented their movement. But in recent constructions of small-hydro, fish ladders are provided and photographs were presented. The presented fish ladder costs as much as 5% of the total project cost. The fish ladder proved to be effective, shown by the number of birds standing by the ladder to catch the moving fish.
But the presence of particular types of fish that move up are noted only in limited locations and in a few kms of river stretches, indicating fish ladders are not required in every weir, but only if such fish movements occur in the concerned region. Environmentalists claim two types of eels have already disappeared. The possibility of captive breeding of endangered species of fish was discussed, in terms of the costs and time. But so far all attempts have been a failure.
Where long channels are constructed it was suggested that channels could be covered in some points or elevated to allow animal crossing for watering purposes.
Deliberate disturbances
Attention was paid to certain hydro-power plants which act against accepted procedures and are careless about damage to the environment due to their connections with politicians. They obstruct the E-flow tube to enhance power generation, regardless of downstream users who depend on released water. Some who seek acceptance of new projects are powerful enough to even transfer GAs who refuse to grant approvals. Others pointed out that flouting the law was done by two or three producers and everyone has been accused of same and there is a need to take action against defaulters.
Alternate sources
Attention was also drawn to alternate forms of renewable energy as solar and wind that could replace mini-hydro. It was pointed out that production of 1MW solar energy requires four acres of land and only during the day. Wind too requires large extents of land and the power variation cannot be predicted.
Conclusions
It is accepted that small hydros have contributed to the development of the country without being a burden to the Government. Most economical locations have already been developed and remaining locations are marginal or delayed due to local problems. Also the new development project sites generating less than 1MW have been disallowed.
The developers accept concerns raised by the environmentalists especially on disturbing local fish varieties, but are concerned when a developer has spent millions in preparatory works and permission to proceed is then denied. It was suggested that the Sustainable Energy Authority identify sensitive areas and publicise such locations, thereby preventing unnecessary expenditure by prospective investors. Environmentalists could help by pointing out sections of streams that are habitats of endangered species.
In the design of weirs simple solutions such as slight changes to design, inclusion of fish ladders, modified surface finishes and inclusion of cascades would help to address sensitive issues. Even after construction of a plant, implementation of best practices could improve sustainability.
Power plants already constructed which have recorded poor practices need to be inspected and adjustments must be recommended to address issues which will positively address the impact on the environment. Regular monitoring of all power plants would improve the overall situation. In future approval of power plants as E-flow scientifically determined quantities should be enforced.
It was noted that some reports submitted for environment approval are of poor quality produced by unqualified persons acting as consultants. Lack of experts on environment approval issues is hindering the process and it was suggested that the Government should evaluate the consultants and be given CIA registration.
Writer’s comments – E-Flow from Wikipedia
I quote: “Until 1960s, water management in developed nations focused largely on flood protection, water supplies and hydropower generation. During the 1970s, scientists prompted to seek ways to modify dam operations to maintain fish species in streams. The focus was on determining the minimum flow necessary to preserve an individual species in a river referred to as ‘minimum flows’. Since 1990s, restoring and maintaining environmental flows to maintain full spectrum of riverine species, processes and services.
“In 2007, the Brisbane Declaration on Environmental Flows was endorsed by more than 50 countries. The declaration announced a pledge to work together to protect and restore the world’s rivers and lakes. By 2010, many countries throughout the world had adopted environmental flow policies, although their implementation remains a challenge.”
The above shows E-flow is a recent sentiment and was not in existence when our large dams were built or during the approval of initial small-hydro plants. Thus blaming early developers does not serve any purpose. Some early plants may require minor modifications as increase of E-flow and fish ladders. As the requirement was not identified during the building of the weir, the costs involved need to be shared between the producer and the Government.
Other issues
The loud noise made by the environmentalists makes one imagine that small-hydro developers are the only culprits who disturb the environment. Apart from the environmentally damaging industries, how about the persons who use dynamite in rivers to collect fish after blasts, destroying the entire habitat? The illegal loggers who cut down trees to extract valuable logs from forests?
During the past few months with the drought, hundreds of acres of forests and grasslands were burnt resulting from fires started by villagers for hunting and to feed their cattle on new grass. Unfortunately, not a single culprit was charged in court, although the whole village including the Grama Sevaka is aware of the culprit. Farmers, encouraged by politicians, continue to encroach into wildlife reserves. Cattle farmers divert their herds into tank beds, deprive elephants of their grass and complain that elephants invade their farmlands and damage their houses. We rarely see environmentalists complain about the above issues.
While appreciating concerns of environmentalists on vanishing fish in streams, how about vanishing innocent land animals such as the slender loris, which were common in suburban gardens few decades ago? Also what can be done about exploding populations of monkeys, porcupines and peacocks, which damage farmers’ crops?
The seminar brought three parties with different interests and aired their views in public. At the end they wowed to continue their discussions and hopefully will respect each other’s views and settle their differences to reach an agreement for the benefit for the country.
