The debate how much is minimum
Run of the river dams involve diverting the river into a tunnel, ranging from 3 km to more than 15 km long. Since it will be a cascade of dams
throughout the river, most of it will flow through either tunnels or small reservoirs. The place from where the river is diverted into a tunnel to the
point where it is released back into its natural stream tends to have very little water, especially during the lean season, winters for instance (see
box
Enter the tunnel). The water is important to sustain the ecology and nearby groundwater aquifers. This has led to a debate on how
much flow is needed to sustain these.
The Union Ministry of Environment and Forests (
mo
ef) says there is no use of having a
designated minimum flow for all rivers."It is different for different rivers and depends on how much flow is needed for ecological sustenance in
that area. Earlier, the exact amount of flow needed was not mentioned in the environmental impact assessment (
eia) reports but now we do give a specific figure in the clearance," said S Bhowmik, additional director, Impact
Assessment,
mo
ef. In the clearance letters to the recent hydroelectric projects on the
river basins, the ministry has said that the projects should maintain a minimum flow of 30 cusecs (<1 cumec)="" in="" the="" lean="" season.="" "no="" one="" knows="" the="" basis="" of="" this="" 30="" cusecs,"="" says="" ritwick="" dutta,="" the="" lawyer="" fighting="" cases="" against="" some="" of="" the="" hydroelectric="" projects="" in="">1>
Since
eias require projects to maintain a minimum flow in the river at all times, they calculate it by tracing 30-40
years of old flow data of a river, provided by the Central Water Commission. But the
eias in the case of most
projects show that they have not taken any of these concerns seriously. Only two projects'
eias--Alaknanda and
Pala Maneri--say that 10 per cent of the lean season flow and 2 m
3 /second should be released respectively. For Alaknanda
though, the minimum flow has not been mentioned. In the case of Pala Maneri, it works out to just 6.7 per cent of lean season flow.
Himachal Pradesh is the only state to have come out with a notification on minimum flow. The state government said that a minimum flow of 15
per cent of the lean season should be maintained by hydroelectric projects. "Diversion of huge quantities of water (from the Sutlej and Chenab
rivers) by hydel projects has minimized water flow or even dried up the main river bed...which consequently is not only damaging the water
course but also causing irrigation problems, health hazards and waterborne diseases. Decreased volume of water is a cause of pollution of
water streams," the notification states. The National Hydroelectric Power Corporation Ltd (
nhpc) challenged this
notification in the Himachal Pradesh High Court. "We challenged the notification because it is not possible for us to maintain the criterion in
projects that are already operational. They have not been designed like that. So, the high court stayed the notification for the existing projects,"
Usha Bhat, chief of environment department at
nhpc, said. The court has constituted an expert committee to look
into how much minimum flow is needed for the upcoming projects, she added.
Criticizing the move, Vidhya Soundarajan, senior coordinator, Policy and Programme Development,
wwf, said
"10-15 per cent flow of the lean season is a trickle.
India has just picked up figures from rivers like Mississippi and Amazon that are usually
flooded." Calling minimum flow a "dubious term", Soundarajan adds, "Minimum flow is calculated from the point of view of human needs. What we
need to deliberate on is the environmental flow which takes into account the groundwater recharge potential of the river, irrigation, urban needs,
ecology, dissolved oxygen and silt load factor."
For example, otters, an endangered species, and mahaseer are found in the area where the Kotli Bhel I b project (near Devprayag, the meeting
point of the Alaknanda and Bhagirathi) is proposed. "A mahaseer needs a fast flowing river for laying eggs while the habitat of otter is in the
riparian groves near the Alaknanda river. If the dam comes up, their population will suffer due to very little change in the water levels," Dutta said.
The National Environment Appellate Authority (
neaa), which has heard cases against Pala Maneri and Loharinag
Pala projects, is currently hearing the Kotli Bhel I b petition. "
neaa did cite the need for a cumulative assessment of
all dams and their impact on the flow in case of Pala Maneri. In Loharinag Pala, the authority directed the
mo
ef to monitor the environment and ecology of the area," Dutta added. The ambitious Kotli Bhel
eia proposes to catch otters from their natural habitat between Dev Prayag and Srinagar and resettle them in the area
between Kirti Nagar and Srinagar, which will be declared a Protected Area. There are dime-a-dozen errors in the
eias done for the projects.
Little awareness The first sentence in the chapter on prediction of impacts in the
eia of Vishnugad Pipalkoti Hydroelectric Project in the Alaknanda basin reads "Based on project details and the
baseline environmental status, potential impacts as a result of the construction and operation of the proposed Teesta-
iii hep have been identified." Teesta
iii is a project in
Sikkim, the
eia of which was done by Water and Power Consultancy Services Limited (
wapcos), the company that has also done the
eia for Vishnugad Pipalkoti project.
Numerous such examples exist.
Another problem with the
eias is dated data. The
eia for Pala Maneri, prepared in
2005, used data from the project report of 1986 which says that the average minimum (non-monsoon) discharge of the river at the dam site is
30.87 cumecs. Currently, at the Loharinag Pala site, the project above Pala Maneri, the average minimum discharge in the river is about 18
cumecs, according to
ntpc. The
eia of Pala Maneri mentions names of villagers who
participated in the public hearing. "Of those, two people were already dead. This shows how credible the hearing was," said R Sreedhar of
Environics Trust, New Delhi (see box
Behind closed door).
The
eia of Srinagar has taken the flow data from 1971 to 1994, which gives only the average flow over those 23
years. The three Kotli Bhel
eias and the Srinagar
eia have not quoted the source of
this flow data while that of Loharinag Pala says it is taken from the detailed project report. The Central Water Commission (
cwc) refused to divulge the flow data saying the Ganga is a "sensitive river".
"There has certainly been a change in
discharge of the river over the past few years. Even the silt content in the river has gone up due to deforestation," said A K Bajaj, chairperson of
cwc.
According to Ishwarchand, assistant engineer of Maneri Bhali II, the silt load at the barrage site there is 90 million tonnes per annum. There is no
estimation of the silt in the Ganga downstream of Tehri. "Tackling silt takes up to 20-30 per cent of the project cost. Projects now use the latest
technology to tackle silt," said Bajaj. But
eias are silent on the silt problem. "Increase in silt is also due to
constructions upstream," a guard there said. "This indicates that none of the dams can work properly till all construction is over," said R S
Jamwal, who runs a school in Uttarkashi. Parts of generation units underwater in Maneri Bhai I have been damaged because of silt.
The section on fish management in the
eias of Tapovan Vishnuagad, Lata Tapovan and Vishnugad Pipalkoti, all
done by
wapcos, reads the same. The Kotli Bhel
eias have an identical statement
"Operation Phase Improved habitat for birds, reptiles, mammals, amphibians and plankton due to reservoir creation." Claiming that "nothing
could be further from the truth", scientists of Environmental Law Alliance Worldwide (
elaw),
usa, who conducted an evaluation of these
eias, said, "The kind of habitat surrounding a
reservoir, in terms of types of vegetation and biological diversity, is vastly diminished and altered compared to the types of riparian vegetation
and diversity that surround free-flowing river segments. The Loharinag Pala
eia mentions that the total forestland
that will come under the project will be 60 hectares (ha). According to the Uttarkashi Forest Division, it is 139 ha. "Most
eias have picked up secondary data. No direct study, just a copy and paste job. In effect, there has been no impact
assessment," said Sreedhar.
There are several more reasons to be concerned about the feasibility of run of the river projects, say experts, for the
eias have completely ignored some important aspects such as laying of transmission lines, flashflood possibilities and
glacial melt (see box
Climate uncertainties). Heat generated by high-voltage power transmission lines is enough to destroy agriculture in
the areas from where they pass and cause extensive loss of forests and habitat fragmentation. Flash floods caused because of landslides could
be a major problem. The 1978 flash flood of Kanodiya Gad, upstream of which the Loharinag Pala is coming up, serves as an instance. The
gad (stream) was blocked by a huge rock that fell from the mountain. When the water pressure built up, the rock moved towards
Bhagirathi and created a huge lake there.
Downstream impact Silt, crucial for farmers downstream, getting trapped in these dams will adversely impact
downstream areas, mainly the Indo-Gangetic plains. "Gangetic rivers erode bulk of the sediments from upstream areas in the Himalayas and
deposit part of it in the alluvial plains and a significant part in the Bay of Bengal," Jhunjhunwala quotes a study.
The
eia of hydropower projects ignore this impact on downstream areas. The
eia of
Srinagar hydroelectric project says "The annual silt load in the dam is 7.62 mm
3 and in due course of time (9.184 years) the dead
storage will be silted up.
However, as the spillway gates will be frequently operated, the accumulated silt behind the gates will be flushed out."
Jhunjhunwala argues that the silting up of the dead storage implies that downstream areas will be deprived of this huge amount of sediment.
"Flushing will only remove silt behind the gates, leaving silt in the larger dead storage trapped perpetually," he added.
According to the
elaw report, trapping of silt would make the Ganga a "hungry river" in the downstream. "As the
dams will dramatically decrease sediment supply in the water, they will behave as "hungry waters" scouring sediment from the riverbeds and river
banks downstream of the dams to restore the natural sediment levels of this water. Fisheries several kilometers downstream will be adversely
affected because of impairment to the biological food chain that is fortified by the muddy sediment layer."