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ENVIS Technical Report 91,   April 2015
ENVIRONMENTAL FLOW ASSESSMENT IN YETTINAHOLE:
WHERE IS 24 TMC TO DIVERT?
1Energy & Wetlands Research Group, Centre for Ecological Sciences, 2Centre for Sustainable Technologies (astra),
3Centre for infrastructure, Sustainable Transportation and Urban Planning [CiSTUP], Indian Institute of Science, Bangalore, Karnataka, 560 012, India.
E Mail: cestvr@ces.iisc.ernet.in; vinay@ces.iisc.ernet.in; bharath@ces.iisc.ernet.in, Tel: 91-080-22933099, 2293 3503 extn 101, 107, 113
Executive Summary

Western Ghats are the mountain ranges extending from southern tip of India (Tamil nadu – Kanyakumari) to Gujarat. These mountain ranges are rich in biodiversity with diverse and endemic flora and fauna, and is birth place to numerous perennial rivers namely Netravathi, Sita, Sharavathi, Aghanashini, Krishna, Cauvery, etc. The Western Ghats hill ranges forms an important watershed for the entire peninsular India, being the source of 37 west flowing rivers and three major east flowing rivers and their numerous tributaries. The stretch of Central Western Ghats of Karnataka, from 12°N to 14°N, from Kodagu district to the south of Uttara Kannada district, and covering the Western portions of Hassan, Chikmagalur and Shimoga districts, is exceptionally rich in flora and fauna. Whereas the elevation from 400 m to 800 m, is covered with evergreen to semi-evergreen climax forests and their various stages of degradation, especially around human habitations, the higher altitudes, rising up to 1700 m, are covered with evergreen forests especially along stream courses and rich grasslands in between. This portion of Karnataka Western Ghats is extremely important for agriculture and horticultural crops. Whereas the rice fields in valleys are irrigated with numerous perennial streams from forested hill-slopes the undulating landscape is used to great extent for growing precious cash crops, especially coffee and cardamom. Black pepper, ginger, arecanut, coconut, rubber are notable crops here, in addition to various fruit trees and vegetables. Some of the higher altitudes are under cultivation of tea. Conservation and sustainable management of central Western Ghats are extremely important from the point of productivity, revenue generation, employment potential and subsistence.

Forests in the Western Ghats along with the soil characteristics and precipitation plays a major role in storing water during monsoon, and releases to the streams during post monsoon periods catering to the needs of the dependent biota including humans. Some of these undisturbed/unaltered natural flow conditions in rivers and streams have proved their value with presence of very rich and diverse species, which also has helped in sustaining the livelihood of dependent populations. The undisturbed flow conditions meeting the ecological and social needs are referred to as ecological flow / environmental flow.

Environmental/Ecological Flow is defined as “Minimum flow of water maintained in a water body (river, lake, etc.) sustaining ecosystem functions”. Understanding environmental flow is important in order to evaluate and understand the role of  the water body in catering to the ecological and social (people, agriculture and horticulture, etc.) needs in a sustained and balanced way. The maximum capacity up to which water as a resource catering all demands of the dependent biota is referred as carrying capacity of water resource. The carrying capacity refers to the maximum number of activities (biological, developmental, agricultural, and industrial, population) that is supported over a period of time in the habitat without damaging the:

  • Existing quality of life,
  • Balance of resources, ecology and productivity of the ecosystem.

Ecological Carrying Capacity provides physical limits as the maximum rate of resource usage and discharge of waste that can be sustained for economic development in the region. This provides theoretical basis with practical relevance for the sustainable development of a region. Carrying capacity of a river basin refers to the maximum amount  of  water  available  naturally  as stream  flow,  soil  moisture  etc.,  to  meet  ecological  and social  (domestic,  irrigation  and  livestock)  demands  in  a  river  basin.
Environmental flow assessment of Yettinaholé river has been carried out based on the analysis of land use dynamics (using remote sensing data), meteorological data (rainfall, temperature, etc. from IMD, Pune),  hydrological data (from gauged streams) apart from field investigations to quantify water yield in a catchment.

Yettinaholé catchment extend from 12044’N to 12058’N Latitude and 75037’E to 75047’E longitude encompassing total area of 179.68 km2. The terrain is undulating with altitude varying from 666 m above MSL to 1292 m above MSL leading to higher density of stream network. Geologically, rock types consists of Gneiss, the soils are loamy ranging from sandy loamy to clay loamy. Soils in the region are fertile and highly permeable, hence allowing the precipitated water to percolate easily into the subsurface recharging ground water and storing water in the sub surfaces and hence keeping the water source perennial to the catchment and the downstream users during and post monsoon.
Karnataka Neeravari Nigam Limited, Government of Karnataka has proposed to divert and store the water to meet the needs of the water scares regions: Kaduru, Arsikere, Tipturu, Chikkanayakanahalli, Gubbi, Madhugiri, T.G.Halli, Ramnagara, Gouribidnuru, Nelamangala, Hesaraghatta, Doddaballapura, Hoskote, Devanahalli, Chikkaballapura, Gudibande, Bagepalli, Chintamani, Srinivasapura, Sidlaghatta, Maluru, Kolar, Mulbaglu and Bangarpete at an estimated cost of 12,912 crores. The proposed weirs have overall catchment area of 176 sq.km with evergreen forests dominating the catchment to an extent of 45.05%, followed by agriculture plantations (coconut/arecanut) about 29.25% and grass lands about 24.06%. The presence of these thick evergreen forests and grass lands in the catchment are responsible for higher infiltration and perennial streams. Any anthropogenic activities involving large scale land cover changes would affect the hydrology of the river basin affecting the dependent biota. The region’s ecological and economic importance is evident from

  • Yettinaholé and its immediate neighboring catchments falls under the Ecological Sensitive Zone 1 (ESZ 1) (HLWG report of Western Ghats conservation, http://envfor.nic.in/sites/default/files/HLWG-Report-Part-1_0.pdf) and as per the recommendations of the working group there shall be strictly no developmental activities.
  • The region is vulnerable and prone to frequent human animal conflict (Elephant Human conflict) as per the Karnataka Elephant Task Force (KETF: (i) http://envfor.nic.in/content/report-karnataka-elephant-task-force-submitted-honourable-high-court-karnataka?theme=moef_high, (ii) http://www.atree.org/sites/ default/files/KETF%20Final%20Report%20SCREEN%20RES.pdf#page=14&zoom=auto,-12,418), and any alterations in the elephant corridors would enhance human animal conflicts threatening the survival of elephants.

The catchments receive annual rainfall of 3000 – 4500 mm (Department of Statistics, Government of Karnataka). Water yield in the catchment computed for each of sub-catchments based on the current land use and other related hydrological parameters using empirical method. The total runoff yield from the catchments is estimated to be 9.55 TMC in contrast to the estimated 24TMC in the DPR (detailed Project report prepared by Karnataka Neeravari Nigam Limited, Government of Karnataka) or 22 TMC (as per KPC: Karanataka Power Corporation). The inflated values of water yield in the catchment would only lead to the failure of water diversion scheme similar to Telugu Ganga Project. Implementation of the project would affect the livelihood of dependent population (current users in Yettinaholé catchment) and would not benefit the likely beneficiaries in arid regions of Karnataka.   


Highlights of the current analysis are:

Water yield in Yettinholé catchment:

9.55 TMC

Domestic, crop water, livestock water demand:

5.84 TMC

Environmental flow to be maintained (to sustain ecosystems):

2.86 TMC

Yettinaholé diversion project if implemented will not help either the residents of arid regions in Karnataka (Chikballapur, Kolar, Tumkur) or local people in Gundia river basin. Residents of Yettinaholé catchment would be deprived of their right for water, while people in the arid regions would only get to see dry canals, etc. Implementation of Yettinaholé project would lead to water scarcity in Hassan and Mangalore, and will not benefit Chikkballapur, Kolar, etc. Livelihood of Yettinaholé and Gundia catchment would be affected severely due to lowered agricultural and fisheries yield similar to the residents of Nellore district with the implementation of  Telugu-Ganga project. The project if implemented deprives the local people their right to water under Article 21 of the constitution of India

In India, the constitutional right to access to water can be drawn from the right to food, the right to clean environment and the right to health, all of which have been protected under the broad rubric of the Right to Life guaranteed under Article 21 of the constitution. In addition to article 21, Article 39 (b) of the directive principles of state policy (DPSP), which the Constitution declares to be non-justiciable, recognizes the principle of equal access to the material resources of the community. Article 39 (b) mandates that ‘the State shall, in particular, direct its policy towards securing that the ownership and control of the material resources of the community are so distributed as best to subserve the common good.’

The precautionary principle articulated in the constitution prescribes that: (i) the environmental measures taken by the state and the statutory authorities must anticipate, prevent and attack the causes of environmental degradation; (ii) that where there are threats of serious and irreversible damage, lack of scientific certainty should not be used as a reason for posting measures to prevent environmental degradation; and (iii) that the ‘onus of proof’ is on the actor or the project proponent to show that his action is environmentally benign.
“The constitutional and statutory provisions protect a person’s right to fresh air, clean water and pollution-free environment, but the source of the right is the inalienable common law right of clean environment.”
(Hon’ble Supreme Court’s observation in Vellore Citizens Welfare Forum (n 7) at pg. 661)

Gundia River is formed by the streams namely Yettinaholé and Kempholé to which the streams Kadumaneholé and Hongadahallé join in the course. The Gundia catchment region is surrounded Hemavathi river water-shed on its right, Barapole river catchment on its left and Netravathi River on downstream side. The Gundia catchment comes under influence of the South-west monsoon i