Nov 27, 2015 - Road Map to Develop and Manage Water Resources in Goa State ..... Authors also express their thanks to all the Scientists of CGWBwho are.
Government of India Ministry of Water Resources, River Development & Ganga Rejuvenation Central Ground Water Board South Western Region Bangalore
Jal Kranti Abhiyan 2015-16
Proceedings of the National Workshop on
Water Conservation, Water Security and Water Quality
Venue: Goa Science Centre, Panaji, Goa 27th November 2015
CONTENTS Sl. No.
Title
Page No.
1
Hydrogeological Evaluation of a Watershed with Mining activities: Case Study of Salaulim reservoir, Goa, India Ashwini Pai Panandiker and A.G.Chachadi
1-21
2
Results of Ground Water Exploration in Goa State K.M.Viswanath, A.Suresha and J.Davithuraj
22-32
3
Road Map to Develop and Manage Water Resources in Goa State K. R. Sooryanarayana, M. A. Farooqi, J. Sivaramakrishnan and Bijimol Jose
33-44
4
Inter annual variability of Southwest Monsoon Rainfall over Goa V.K. Mini, K.S. Hosalikar and N. Haridasan
45-57
5
Ground water quality studies along the North Goa coast Vidya Sujitha, B. K. Purandara, A. V. Shivapur, Davithuraj
58-71
6
Monsoonal Behaviour of Ground Water Level in Goa State H.P.Jayaprakash, S.S.Hegde, Rakhi.U.R, Lubna Kouser, Hemalatha.V. and J. Sivaramakrishnan
72-79
7
Water Conservation in Agriculture Director, Directorate of Agriculture, Krishi Bhavan, Tonca, Caranzalem-Goa
80-90
8
Conservation and recycling: Approaches to Sustainable Water Management Ulhas G. Sawaiker
91-103
9
Efficacy of Vented dams as water harvesting structure in Goa State Bijimol Bijimol Jose and M. A. Farooqi
104-108
10
Water Security in Changing Climatic and Hydrologic Conditions Mathew K. Jose, Venkatesh B, Purandara B.K, and Chandramohan T
109-140
11
Modelling of Surface-Groundwater interaction in Bellary Nala Catchment, Belagavi, Karnataka B. K. Purandara, Sudhir kumar, B. Venkatesh, M. K. Jose and T. Chandra mohan
141-146
12
Maintenance of Village Water Supply Sources and Schemes of Existing Water Supply Systems in India Raksha A and L.G. Aswathanarayana
147-157
National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
ROAD MAP TO DEVELOP AND MANAGE WATER RESOURCES IN GOA STATE K. R. Sooryanarayana, M. A. Farooqi, J. Sivaramakrishnan & Bijimol Jose Central Ground Water Board, South Western Region, Bangalore, India
Abstract
Goa spread over an area of 3,702 km2, lying between Western Ghats and Arabian Sea, situated at west coast, is the smallest state of India. It is the most attractive destination for tourists from all over the globe due to its scenic beauty, pleasant climate and hospitable nature of the people. The State receives an average rainfall of 3227 mm,but due to highly undulating topography and underlying hard rocks, major part of the rainfall reaches to the Arabian Sea as surface runoff and subterranean flows. Thus, in spite of being blessed with abundant rainfall, the state experiences water scarcity in some parts during lean periods. As per the report of Dynamic Ground Water Resource Estimation (2011), the annual gross dynamic ground water recharge of Goa state is estimated to be 0.24 billion cubic meters (BCM) and with the stage of ground water development a meagre 28% per cent, the entire state has been categorized as “Safe” from ground water development point of view. Due to increasing population, climate change and pollution, use of surface water resources is reaching the optimum level. Although, ground water development in the state, in general, is low, restricted to clusters still now, gradually, pressure on ground water resources will increase, which may lead to mismanagement and over-exploitation of this precious resource. Instances of sea water ingress due to over-exploited clusters and rampant mining have already been reported from parts of the state. There is no mechanism in vogue to address this looming problem. Time has come to address problem with a holistic approach. This paper presents a road map for the sustainable development and management of water resources to provide water security in this tiny state. Keywords: Ground water, Sustainable development, Sea water ingress, Water Security
Introduction Goa, the smallest state of India located in the western region, is bounded by the state of Maharashtra to the north, and by Karnataka to the east and south, while the Arabian Sea forms its western coast. Lying between the
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
latitudes 14°53′54″ N and 15°40′00″ N and longitudes 73°40′33″ E and 74°20′13″ E, Goa state encompasses an area of 3,702 km2. Most of the Goa stateis a part of the coastal country known as the ‘Konkan’ which is an escarpment rising up to the Western Ghats range of mountains, which separate it from the Deccan Plateau. The highest point is the Sonsogor, with an altitude of 1,167 metres. It is administratively divided into two districts and 11 taluks.In view of rapidly growing population, overexploitation of ground water resources, pollution of surface and ground water resources, coupled with adverse impact of climate change, almost entire nation is facing water scarcity, and Goa is no exception.Considering the developmental need of our fast growing country, there is a need to promote as well as consolidate the activities of water conservation, optimization of water-use efficiency and water demand management in the country, through a holistic and integrated approach. It is apprehended that if the water related challenges are not addressed properly, in a time bound manner, the rapidly growing water demand is likely to lead to water conflicts among different user groups as well as the basin States, and the prime objective of providing water security will be seriously jeopardised. Central Ground Water Board has been carrying out studies in different parts of the country including Goa state to provide a road map for sustainable management of water resources. Physiography Physiographically, the Goa State is divided into four morphological units namely, 1.Costal plains with dominant Marine land forms on the west, followed successively towards the east, 2. Vast plain,3. Low dissected denudation hills and tableland, and 4.Deeply dissected high Western Ghat’s denudation hills occurring all along the eastern part of Goa rising to a maximum of 832m above MSL. The Alluvial landforms are limited in
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
areal extent.Goa State forms part of coastal tract of the west coast of India with acoastline of 101 km. Drainage The State of Goa is drained by the west flowing rivers, Terikol, Chapora, Mandovi and Zuari. The Sahyadri hill ranges in the east form the main watershed. The streams originating here flow in westerly and northwesterly direction to join the Arabian Sea. Major portion of the State is drained by the two rivers, viz. River Mondovi and river Zuari and nonperennial (seasonal) river Baga. The river Terikol forms the northern boundary of Goa State and separates it from the Maharashtra State. The other smaller rivers draining the State are the rivers Chapora, Baga, Saleri, Sal, Talpona and Galgibag (Table-1). Primarily the underlying rocks govern the drainage system in the area. The drainage pattern is generally dendritic type. The major river Zuari follows the major NW synclinal axis. The river valleys are ‘V’ shaped in the western high hill ranges, but broadens in central midlands and become ‘U’ shaped in the low lands and coastal plains. Table-1: Details of the Major/Minor river Basin area in Goa State Area
Drainage Basin / Sub Basin Terekol Chapora Baga
Km2 49 272 53
% 1.32 7.35 1.43
Mandovi
1594
43.06
Zuari
913
24.66
Sal Saleri Talpona Galgibag
404 113 226 78 3702
10.91 3.05 6.1 2.11 100
Total
Taluks Pernem, Pernem, Bicholim, Bardez, Bardez Bicholim, Bardez, Satari, Sanguem, Tiswadi, PondaandCanacona Tiswadi, Ponda, Salcete, Quepem, MarmugaoSanguemandCanacona Marmugao, Salcete, QuepemandCanacona Quepem andCanacona CanaconaandSanguem Canacona
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
Rainfall Rain occurs during the monsoon period from June to September. Over 90 percent of annual rainfall occurs during monsoon period. The balance of 10 percent occurs during the pre-monsoon period from March to May and post monsoon period from October to December. However the rainy period extends from May to November. It is reported that during March 2008 Goa was lashed out with heavy rain and strong winds. This was the first time in 29 years,that Goa had seen rain during the month of March. The analysis of Rainfall data for the period of 1970 to 2000 from 12 stations over the Goa State indicates that the monsoon rainfall is in the order of 3160.06mm (90.74 % of annual rainfall), 218.1mm (6.26%) during post monsoon period of October to December and 104.42mm (3.99%) are from January to May months. The overall annual rainfall over the Goa State based on 30 years rainfall data is of 3483.3mm. The minimum rainfall of 2611.7mm is recorded at Mormugao station falls in South Goa and maximum of 5090mm is in Sanguem station also from South Goa. Hydrogeological Conditions Major part of the Goa State is underlain by rocks of Precambrian age comprising of banded biotite gneisses, meta-volcanics, phyllites, biotite and chlorite schists, greywacke, conglomerate (tilloid), pink phyllites with associated banded ferruginous quartzite and chart breccia. These rocks are intruded by ultra-basic, basic sills and dykes, followed by granites and pegmatites. Dolerite dykes and quartz veins form the youngest intrusives in the area. The Deccan Trap basalts of Late Cretaceous to Early Eocene age occupy a small portion in the north-eastern part in the high altitudes. Almost all the formations in the State have undergone lateritisation to
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
various degrees depending upon the climate and rock type. The lateritisation is more pronounced in the coastal areas than in the hilly regions and phyllites, schists and meta-volcanics are more susceptible to lateritisation and the gneissic/granitic rocks are least susceptible. In general the thickness of laterites varies from about 3 to 30 m. Laterites are highly porous due to the process of leaching and weathering they have undergone during their formation and hence have very good capacity to hold and transmit groundwater. Groundwater in laterites occurs under phreatic conditions. Major portion of the State is occupied mainly by crystalline rocks and consolidated and metamorphosed sedimentaries, which do not possess primary porosity. Secondary porosity, introduced in them through weathering, fracturing and jointing, produces the avenues to hold and transmit ground water. Groundwater in these rocks occurs under watertable conditions in the weathered zone and under phreatic to semiconfined and confined conditions in the deeper fractured zone. Beach sands along the coast and alluvium along major rivers have limited occurrence and the ground water in them occurs in the primary porosity under water-table conditions. Ground Water Resources Groundwater resources of Goa were estimated taking taluk as unit for the base year 2011. There are 11 taluks. The taluks were divided into sub units of command, non-command, poor quality and hilly areas and resources were estimated for each of the units excluding the hilly areas. Hilly areas having slope of more than 20% are supposed to have very quick run off and contribute little recharge to the ground water. There are 20 sub units for which the resources were estimated. Similarly the areas having
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
massive rock exposures are also not suitable for augmenting recharge to ground water. Hence, such areas are excluded from recharge calculations. The recharge to ground water is computed separately for monsoon and nonmonsoon months using both, water table fluctuation method and rainfall infiltration method. The net annual groundwater availability as on March 2011 for the state of Goa is 14543 HAM, while the gross annual draft is 4114 HAM, and the net available resource for future irrigation development is 9689 HAM. Taluk wise and command/non-command wise resources are given in Table.2. The average stage of ground water development in North Goa district is 30% with Pernem taluk recording the lowest stage of development of 15% in command and 16% in non-command area, while Bardez taluk recording the highest stage of development of 39% in the command and 46% in the non-command area. In respect of south Goa district, the average stage of development is 26% with Sanguem taluk recording the lowest stage of development of 11% in Command and 12% in non-command area, while Salcete taluk has recorded the highest stage of development of 40% in command and 45% in non-command area. The overall stage of ground water development in the state of Goa is 28% and all the taluks are falling under safe category.
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
Table.2. Dynamic Ground Water Resources of Goa (as on March 2011)
Stage of Ground water Development (%)
Net annual ground water availability for future irrigation development
Provision for Domestc and Indutrial Water Requirement to 2025
Existing Ground water Draft for All uses
Command/ Noncommand
Existing Ground water Draft for Irrigation
Assessment Unit / Taluk
Net Annual Ground water Availability
Sl No
Existing Ground water Draft for Domestic and Industrial water supply
(in ham)
NORTH GOA
1 2 2A
TISWADI BARDEZ BARDEZ
3 3A
PERNEM PERNEM
4 4A
BICHOLIM BICHOLIM
5 5A
SATARI SATARI
6 6A
PONDA PONDA
NONCOMMAND COMMAND NONCOMMAND
1325 619 1154
96 60 184
369 183 342
465 243 525
457 227 423
772 332 547
35 39 46
TOTAL
1773
244
525
769
650
879
43
COMMAND NONCOMMAND
477 1140
22 67
49 117
61 145
394 928
15 16
TOTAL
1618
89
166
206
1323
16
COMMAND NONCOMMAND
633 1129
33 149
75 134
71 184 255 108 283
93 166
508 814
17 25
TOTAL
1762
182
209
391
259
1321
22
COMMAND NONCOMMAND
80 737
6 123
13 122
20 245
16 151
57 462
25 33
TOTAL
817
130
135
265
167
520
32
COMMAND NONCOMMAND
10 1249
0 38
3 342
3 380
3 423
6 788
28 30
TOTAL
1259
38
345
382
427
795
30
DISTRICT TOTAL
8554
778
1750
2527
2166
5610
30
SOUTH GOA
7 7A
SANGUEM SANGUEM
8 8A
CANCONA CANCONA
9 9A
QUEPEM QUEPEM
10 SALCETE 10A SALCETE 11
COMMAND NONCOMMAND
21 1407
0 18
2 146
2 164
3 180
18 1209
11 12
TOTAL
1429
18
148
166
183
1227
12
COMMAND NONCOMMAND
10 577
0 25
2 100
2 125
2 123
8 428
18 22
TOTAL
587
25
101
127
126
436
22
COMMAND NONCOMMAND
242 768
5 2
41 130
45 132
51 161
186 605
19 17
TOTAL
1009
7
171
178
211
791
18
COMMAND NONCOMMAND
41 1638
2 150
15 590
16 740
18 730
21 758
40 45
TOTAL
1679
151
604
756
748
779
45
1285
26
334
360
414
845
28
5989
228
1359
1586
1682
4079
26
14543
1005
3108
4114
3849
9689
28
MARMUGAO NONCOMMAND DISTRICT TOTAL STATE TOTAL
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
Constraints in meeting the water requirements Although the state is blessed with bountiful rainfall and huge potential of assured water, scarcity of this precious resource is experienced during lean periods in parts of this tiny state. Possible reasons for these scarce conditions may be attributed to following • Scarcity of ground water during summer months due to high subsurface run-off in hilly topography and highly permeable nature of phreatic aquifer. This results in lowering of water level and even drying of wells during summer months • Ground water in dug wells and borewells in areas around Baga and along Chapora river is brackish to saline due to seawater ingress. • Rampant and unscientific disposal of solid and industrial waste. Ground water in areas adjacent to stream course in northeast of Panjim town is polluted due to domestic sewage. • Indiscriminate mining and its adverse impact on ground water regime. • Heavy water demand by tourism industry due to floating population. Possible Local Solutions for Meeting Unsatisfied Demands • Harnessing non-monsoon base flow in streams and rivers to the maximum extent and utilizing the harnessed water for drinking and other uses. • Construction of Water conservation, artificial recharge structures and Roof top Rain Water Harvesting are to be taken up in water deficit areas, urban areas and quality affected areas to maintain the sustainability and improving quality. • The non-committed sub-surface run off (base-flow) available in streams/rivers in coastal areas can be harvested through vented dams, which are most ideally suited for such terrains.
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
• Use of existing wells drilled by Central Ground Water Board/ State Ground Water Department for augmenting water supply to the optimum level. • Restriction of pumping hours in Coastal areas to preventsaline intrusion. • Organizing capacity building, awareness programs at panchayat level and for school children on water conservation. •
Decentralized garbage/waste treatment systems to prevent further contamination of fresh water resources especially in tourist spots of coastal tracts.
• Encouragement for water-efficient fixtures in domestic use and adoption of micro-irrigation techniques. • Management plan can be formulated by the users based on information from publications like Atlas of aquifer systems of Goa, Master plan for artificial recharge and district information booklets available in website www.cgwb.gov.in and similar publications from Water Resource Department, Government of Goa and other agencies.
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
Road Map to Manage Water for Growth • Sustainable
management
of
ground
water
resource
through
scientific/holistic approach of aquifer systems, through the Flagship programme of NAQUIM taken up by CGWB under XII and XIII Plan. • Periodical assessment of ground water resources. • Implementation of water conservation schemes on large scale by involving the beneficiaries • Improving the monitoring network of ground water levels and quality is essential for arriving village-wise ground water budget and management plan. • Regulate indiscriminate drilling of bore wells, unscientific mining activities and industrial waste disposal. • Change in Irrigation Pattern, Cropping Pattern, restricting free power supply if any, to farmers. Water intensive crops should be avoided as far as possible in ground water deficit/stressed areas. • Co-ordinated efforts amongst various Central and State Government agencies, non-Governmental and social service organizations, academic institutions for evolving and implementing suitable ground water management strategies. • Regulation of pumping hours in coastal areas for preventing saline water ingress. • Sensitization and capacity building of stake-holders on Water conservation issues
for judicious
management and long-term
sustainability. • Use of ground water for tourism industry needs checks to avoid ground water pollution as the tourism zones are distributed along the highly vulnerable coastal tract.
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National Workshop on "Water Conservation, Water Security & Water Quality" CGWB, SWR, 2015
Ground water Development Strategy Deeper ground water abstraction structures should be at least 0.5 km away from creeks and 400m away from coastline in low-lying areas to avoid quality problems. Due to complexities of formations, structure and morphological control, ground water development through shallow dug wells is ideal for the area. Caution is to be exercised while ground water is developed through bore wells. Deeper ground water abstraction structures should be at least 0.5 km away from coast line in low lying areas to avoid quality problems. Ground water occurring in dug wells as well as bore wells is brackish to saline in areas adjacent to the coast and tidal areas due to seawater ingress in inland aquifers. Salinity is more pronounced during May when fresh water flow is at minimum and hence maximum seawater ingress takes place. Investigations have revealed that ground water adjacent to stream course in the north east of Panaji is also polluted due to domestic sewage in addition to salinity problem. Hence, periodical ground quality monitoring is a must for the area to use the ground water for potable purpose. Acknowledgements The authors are thankful to Sri. K.B.Biswas, Chairman, Central Ground Water Board and the Member (WQ&TT) Central Ground Water Board, for providing the opportunity to present the paper in the Workshop. Authors also express their thanks to all the Scientists of CGWBwho are continuously toiling in the field to collect invaluable data and, who havefrom time to time provided much needed input by way of suggestions and technical discussions.
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