Coastal Erosion Control through Installation of Geo-textile Tube Embankment
A study on “Shoreline changes in Odisha” by Ministry of Environment & Forest and Climate Change, Government of India revealed that the coastline of Odisha is largely accreting (46.8%) and 14.4% is stable and 2.00% of the coast is artificial. Erosion (High, Medium and Low) accounts for 36.8% of the coast and out of 480 Km of the coast, only 8.2% are undergoing high erosion. One of the major reasons behind this erosion is regular storm surge and floods in the coastal districts of the State.
Pentha (20° - 32’ – 5’’N) (86° - 47’ – 5”E ) is an agricultural village in Kendrapada district along Dhamra – Paradeep stretch. The region connected with different rivers is Brahmani, Baitarani, Chinchiri, Pathsala, Maipura, Kharasrota, Barunei and Dhamara. The general topography is irregular with many drain cuts, rivers, lakes, ponds, swamps, estuaries, and lagoons. The coast is also known for sporadic nesting by Olive Ridley Turtles. The beach was separated by an earthen embankment having a height of approximate 3 meters and a length of about 1.5 Km. Out of this, about 400m long was most vulnerable to seawater intrusion, due to the fact that the coast is prone to erosion. The coastal stretch adjacent to Pentha village had been continuously eroded for the last few years. The site is more hostile with strong waves hitting the bank throughout the year. Seabed slope is sharper. The shoreline of Pentha was shifting towards the countryside.
- In 1960, The shoreline was 4000m away from existing old embankment.
- In 2001, The shoreline was 500m away from existing old embankment.
- In 2005, The shoreline was 200m away from existing old embankment.
- In 2006, The shoreline was 50m away from existing old embankment.
- In 2008, The shoreline was 20m away from existing old embankment.
- In 2009, The shoreline was 5m away from existing old embankment.
- In the year 2009-10, The a retard embankment was constructed on the backside of the old embankment at a distance of 60 meters length.
- Sea waves damaged the existing old embankment during the 2009-10 and the traditional method of protection using wooden stump piling and Big Resin PVC sandbag dumping was done in the year,2011.
- In 2011-12, The shoreline over-ran the old embankment for a length of 400 meters & washed away the embankment for 350-meter length.
In order to protect the coastline at Pentha from vulnerable erosion, Integrated Coastal Zone management (ICZMP) – State Project Management Unit & Department of Water Resources, Government of Odisha has taken up an up-to-date method of soft engineering technology which includes construction of geo-textile embankment under the assistance from the World Bank. It is a pilot project in the state of Odisha in which a structural system is to be developed to face wave action creating a threat to the existing Rajnagar - Gopalpur saline embankment for long-term protection. The success of this pilot project would be considered as a model for similar cases in another vulnerable area, of the coast which will go a long way to prevent the coastal erosion and protect land, property, and life. Besides, it will protect the coast during the natural calamity.
The various services and components are undertaken during the installation period are given below:
- The services of Ocean Engineering Department, IIT (Madras) was commissioned as the project consultant for a survey of the site, preparation of the designs, and provide technical guidance in the installation of geo-textile tube embankment including quality control and monitoring of the work. The consultant selected the site, prepared the design through field investigation and modeling studies.
- The work for construction of the geo-tube embankment was awarded to M/s Garware Wall Ropes Ltd., Pune.
- Length of 505m of shoreline was protected by Geo-Textile-tubes integrating with existing earthen retard embankment. The embankment is having 235 nos. of geo-tube filled with sand slurry and covered with a protective layer of the granitic gabion.
Benefit/ Impact of the Intervention
- Sand accretion in front of geo-tube is noticed.
- Increased the visit of the number of tourist to the site.
- Coastal village of Pentha is protected and less vulnerable to coastal flooding due to cyclones.
- Life and property of villagers of Pentha and other adjacent villages saved from furry of sea tides and waves.
- Agriculture fields of the local communities are saved from saline ingress and thereby the income of communities is enhanced.
- Local villagers gained confidence on the safety and security of their life & property as they have started (i) construction of Pucca house (ii) renovation of their thatched house and (iii) resettlement of people in Pentha who had left the village in the past because of life risky & insecurity.
- During a severe cyclone Hud Hud (12th October 2014) the seaside slope of retard embankment as protected by gabions are not affected at all and the accretion of sand has occurred in front of Geo-tube.
Beachfront Development in Digha
Digha is a popular seaside resort town of West Bengal which has an annual tourist footfall of over 26 lacs. However, due to excessive anthropogenic interventions in recent times, Digha was facing a multitude of problems like unauthorized encumbrances, seepage of sewage, littering of waste on the open shore, unregulated and unplanned hawking zones and all of that have serious repercussions on the coastal ecosystem. ICZM Project has intervened to address these issues so that this popular tourist destination could sustain itself by stabilizing the vital parameters connected to ecological footprints.
During the inception phase of ICZMP, an integrated Beachfront Development Plan was developed in a consultative process through various stakeholders in Digha-Sankarpur area. Digha-Sankarpur Development Authority (DSDA), which is functioning under the aegis of Department of Urban Development, Government of West Bengal has been mandated as the PEA for execution of the works related to Beachfront Development in Digha.
The pilot interventions aimed towards beach cleaning, beach beautification and providing basic civic amenities to the inhabitants of Digha and inbound tourists along with rehabilitation of hawkers that sprawled across the shoreline and congest the pathways leading towards the shore.
Works related to Phase – I of Beachfront Development in Digha have been completed. The assets created under Phase – I include watch towers, beach amenities, open-air theatre, vendor kiosks for hawkers, beach lighting, paving of the promenade, seating arrangements, garbage bins and allied landscaping works.
Hawkers’ rehabilitation was a challenging assignment as it was directly correlated with livelihood security of the coastal community. Consultation in phases was done with the stakeholders including hawkers about every nitty gritty involving the location of vendor kiosks taking into consideration the business opportunities, design, and material used.
Permanent and temporary vendor kiosks were constructed in line with the decisions arrived in the consultation phases. The entire process of removal of unauthorized shanties that encroached upon the beach along with handing over the newly constructed kiosks was implemented in a seamless and consensual manner. The rehabilitated vendors do opine that the new set up not only provides enhanced security with improved visual aesthetics but would also showcase and sell their products more effectively to potential customers.
Beach Beautification which includes paving of pathways adjacent to the shore, installation of decorative lights, well–lit landscaped zones with seating arrangements coupled with better sanitation facilities in place of the dingy encumbrances provides the tourists better visual aesthetics and acoustics in sync with the rhymes of the waves that hugs the shore.
Open Air Theatre has provided the much-needed platform to the community level cultural ecosystem to showcase their artistic flavor in varied folk music and dance forms.
The Beachfront Development work has improved the environment of the sea- coast. Pollution and littering have reduced considerably in the area.
Conservation of Tropical Dry Evergreen Forests Through Community Participation
The coastal area in Vedaranyam is rich in biodiversity, with many unique species of animals and birds apart from religious, historical and cultural diversity. Many ecologically sensitive areas such as mangroves, lagoons, tidal mudflats, swamps and tropical dry evergreen forests are present. The Point Calimere Wildlife Sanctuary near Vedaranyam is a unique mix of grasslands, mudflats, backwaters, sand dunes and Tropical Dry Evergreen Forest (TDEF). The Tropical Dry Evergreen Forest is a unique forest found only in Tamil Nadu and Andhra Pradesh. It is distribution is restricted to the narrow coastal strip from Vishakapattinam in Andhra Pradesh in the north to Ramanathapuram in Tamil Nadu in the south. The dissymmetric climatic condition of this region, where rainfall occurs both during summer and winter monsoon and extended the dry season from March to September, favors development and sustenance of the Tropical Dry Evergreen forest in this narrow strip. The TDEF has a mixture of trees, shrubs, lianas, and herbs and form a complete canopy in pristine condition and provide habitat to a wide variety of animals including insects, amphibians, reptiles, and mammals. However there is hardly any of this forest in pristine condition and most of them are little more than degraded thorny thickets, lacking the inherent nobility of the climax vegetation. The TDEF is currently preserved in the Point Claimer Wildlife Sanctuary and in the coastal sacred groves. In the ICZM project in Vedaranyam, an attempt has been made to establish the TDEF in about 66 acres of village common land with the active participation of Panchayat Raj Institutions and the local community.
Salt Satyagraha Memorial Site
Around Vedaranyam Salt Sathyagraha memorial site the TDEF has been established in about 30 acres of land. Some area of identified land in this area was slightly elevated quite similar to the environmental settings of the natural TDEF in the Point Calimere wildlife sanctuary but these areas were infested with Prosopis juliflora. In these areas, Prosopis trees were uprooted without damaging the Palmyrah and other TDEF plants found naturally there. In some other areas adjacent to the Salt Satyagraha memorial site, the land was relatively low lying and inundated by seawater during the 2004 tsunami and thus, they were slightly saline. In these areas, salt was partially leached out by storing rainwater during the monsoon season and draining it out at the end of the monsoon. This was done seasons and after this, small mounds were created in the tsunami-affected lands by bringing non-saline soil from outside and in these mounds trees of TEDF were planted. As the soil is sandy with poor nutrients, planting site was enriched with nutrients before planting. Pits of size 3 x 3 x 3’ were dug and filled with a mix of farmyard manure, red soil and sand (1:1:1). This helped to retain the moisture and also prevent the salt stress. About 2,116 saplings belonging to 54 species (80 cm tall) were planted with 3 m spacing. The shallow trench was made around the saplings for watering. Mulching was done around each plant during summer. Two rainwater harvesting ponds were dug nearby, to store rainwater for watering the plants. Intensive watering during summer, regular weeding and maintenance were done. The knowledge of the local community played a significant role in identifying the local species and its sylviculture practice. The plantation is being managed by a joint committee consisting members of the Village Development Council (VDC) of the participating villages, namely, Poovanthoppu, Kadinalvayal, Kovilankollai, Kovilthavu and Adhivasi Colony.
A total area of 8 acres of land belongs to the temple of the local deities (Vempadai Iyanar Pidari Amman) and cemetery and also patches of land located around village pond ( Vettukulam) were provided by the Kadinalvayal Panchayat Raj Institution for taking upon the plantation of TDEF trees. These patches of lands were fenced and a total number of 1,066 saplings of timber value, fruit trees, and TDEF species were planted after careful land preparation. These plantations are now being maintained by the Kadinalvayal Panchayat.
Restoration of Coastal Sacred Groves with TDEF Trees
The coastal sacred groves, located around Vedaranaym, act as repositories of TDEF flora and fauna and houses of endemic species of the coastal region. More than 65 woody species have been identified in these coastal sacred groves and nearly 60% of them are evergreen. Apart from this, sacred groves are also rich in medicinal plants. A study in the sacred groves of Cuddalore coastal tracts indicates the presence of more than 80 medicinal plants. However, many of these sacred groves are in various stages of degradation due to the expansion of agriculture, over-exploitation of natural resources, erosion of traditional system of management etc., The project has selected three such sacred groves for raising TDEF tree plantation.
Periyakuthagai Iyanar Sacred Grove
A sacred with tropical dry evergreen forest trees are present in about 8-acre area in Periyakuthagai village, near Vedaranyam. This sacred grove contains well-grown trees of the following species: i) Atalantia monophylla, ii) Garcinia spicata, iii) Streblus asper, iv) Manilkara hexandra, v) Memecylonum bellatum As a part of the project activities, this sacred is being conserved with the participation of the temple committee. The entire sacred is fenced to avoid encroachment and as a measure to fill the gaps in the vegetation saplings of the following species were planted: 20 saplings of Atalantia monophylla, 25 of Garcinia spicata, 6 of Streblus asper-, 35 saplings of Calophyllum inophyllum- and 65 saplings of Memecylonum belated. The survival rate of the plantation is about 76%.
Ayyakranapulam Kalitheratha Iyanar Sacred Grove
This size of this sacred grove is about 10 acre and it is located in the Ayyakaranpulam village. Trees of Lepisanthes tetraphylla, Madhuca lagifolia, Syzygium jambolanum and Streblus asper are common in the sacred grove. The deity Kalitheratha Iyanar is very population within Tamil Nadu as well as among Tamil people settled in many Southeast Asian countries. Hence, the number of visitors to the temple is very high and as a reason, this sacred grove is slowly being encroached for various developmental activities. In order to stop further degradation of the sacred grove, the project worked with the traditional temple committee and fenced the entire area and established facilities for watering, including digging a shallow bore well and establishing overhead tank.
Thennadar Iyanar Sacred Grove
It is located in a village called Thanadar and area of the sacred is 5 acre. It was totally degraded and the entire area was empty when the restoration activities with TDEF plantation was started. About 240 saplings of the following 13 TDEF tree species are being raised in this sacred grove. i) Atalantia monophylla-25, ii) Garcinia spicata-30, iii) Manilkara hexandra-35, iv) Pleurostyia opposite-20, v) Suregada Angustifolia-25, vi) Dioyros ebenumsp-20, vii) Drypetes sepiaria-15, viii) Sapindus marginatus-20 , ix) Mimusops elengi-15, x) Canthium psyorax-5, xi) Glycosmisc Mauritius-20, xii) Muria peniculata-5 and xiii) Lepisaathus tetraphylla-5(240. As in the case of other sacred groves, the entire area was fenced before taking up of the plantation and it is being maintained by the temple committee.
The TDEF plantation was established in about 2 acres of land around in a primary school in a village called Sandhanadevankadu. A total number of 8 species of TDEF were planted along with many fruit bearing trees and102 timber species... The plantation is managed by the Sandhanadevankadu School Eco Development Committee, comprising representatives of Panchayat Raj Institution, District School Authority and MSSRF.
Performance Evaluation-Social Auditing
The performance of the restoration plantation of the tropical dry evergreen forest was evaluated by a social auditing team consisting of representatives of the Tamil Nadu Forest Department (Range Officer) and Horticulture Department, a school teacher, community members and MSSRF staff. The team visited all the sites and interacted with the stakeholders, including committees that are managing the plantations. The team rated the performance as well based on the parameters such as survival percentage, species selected, maintenance and protection. The survival percentage was ranging between 82 and 95.
Replication of the Model
- Panchayat Raj Institution of a village called Pannal replicated TDEF plantation model in 8 acres of panchayat land with the technical guidance of MSSRF. The area is located close to the salt pan and hence, it is saline. It was completed infested with the weed Prosopis juliflora. As a part of the land preparation, all Prosopis juliflora trees were uprooted and the soil was plowed thoroughly to all salt deposited on the surface seep deep into the soil. A pond (0.5 acres) was also constructed in middle for rainwater harvesting. The entire areas were fully fenced.
- Saplings of Mimusops elengi, Millingtonia hortensia, Hibiscus tiliaceus, Cassia fistula, Syzygium jambolanum, Terminalia catappa, Thespesia populnea, Azadirachta indica and Pongamia pinnata were planted. The NREGA scheme was used for the removal of Prosopis, land preparation, fencing, tree plantation, pond construction, regular watering, and monitoring. The money realized by selling Prosopis was also used. Saplings were supplied by the Tamil Nadu Forest Department.
- Rahmath Matriculation Girls Hr Sec school in Muthupet has replicated this model in 12 acres with the technical guidance f MSSRF.