Dhamapur lake dam, nestled snugly amidst lush forests of Sindhudurga district is a glowing example of how an intelligent and sustainable local system can support communities and wildlife. What makes it more special is that it is a freshwater reservoir formed by perhaps one of the oldest earthen dams in Maharashtra. Dhamapur village strong historical links have been proven by the discovery of ancient hero stones, sati stones along with the images of the deities indicating that Dhamapur has been here since at least the Shilahara period (c. 10^th – 11^th century CE).

The dam gets filled with water at an early stage of monsoon. The lake wetland acts as a sponge, recharges the groundwater storage, arrests flood and allows mixing of minerals in the water. There are some 61 minor streams that meet the two major and one middle order streams that feed Dhamapur Lake. Two outlets emerging from Kavadewadi dam and Guramwadi dam also feed water to Dhamapur Lake. It is, therefore, very important to preserve not only Dhamapur Lake but also protects the inlet streams those give this freshwater body a flourished biological existence. Among various unnamed streamlets, one streamlet traditionally known as “Bhurkhyacha Whal” (lat 16.04 long 73.59) is an old streamlet known since ancient time originating from the mountain in Kalse feeds freshwater to Dhamapur Lake. It holds a very ideal site for storage of water by forming valley shape catchment bounded by hills on both sides. The dam is having waste weir of length 26 m constructed in laterite stone. Dam top level is 99.60 m while sill level is 91.60 m. Dhamapur Lake is minor irrigation freshwater body having full reservoir level as 96.80 m while maximum water level of 97.30 m having a flood lift of 0.50 m. Most deciduous forest present around the lake is Reserve forest. Dhamapur lake harbour rich biodiversity with rare species of flora. Crotalaria filipes Benth, Gnetum ula Brong and Nothopegia colebrookiana (wight) Blume rare endangered listed flora are reported at the banks of Dhamapur Lake. Thus, dam site is an ideal place in all respects viz., biodiversity, wise-tourism, nature trail, water supply, irrigation, and fishing.

History

Dhamapur lake dam built in the year 1530 by villagers of Dhamapur and Kalse under the guidance of Nagesh Desai, Mandlik of Vijaynagar dynasty, the dam was built entirely by the local fund. It is the biggest lake in the district and perhaps next only to Tadoba lake. The dam site is situated on Kudal-Malvan road with very good foundation strata. The height of the dam above lowest foundation is 11.43 m while the length is 271 m. The total volume content is 2.867 Mm³ out of which, 2.441 Mm³ is live storage. Dhamapur Lake has a submergence area of 43.30 Ha and a maximum depth of 11.43 m. Total of 9.97 Km² catchment area is feeding rainwater to the lake. The volume content is 2,687 km³ (645 cu mi) and gross storage capacity is 2,867 km³ (688 cu mi).

Water Heritage

Dhamapur Lake made an outstanding contribution to enhancing food production, livelihood opportunities, rural prosperity, and poverty alleviation in a region

Dhamapur Lake an Irrigation Structure is the main source of drinking water and irrigation for the Dhamapur and Kalse Village people. Built in 1530 and still fully functional till this date The Lake has exceptional testimony in the development of the agriculture and increase in the food production of the local villagers.  It has been providing a continuous supply of water over 4 centuries. In meanwhile 1997-2000 a drinking water supply scheme was set-up at Dhamapur tank Municipal Corporation at Dhamapur tank water is pumped and taken to Malvan city 16km away and 4 more villages. As per water user association act 2005, local farmers formed an association named “Shri Bhagavatidevi water user association” to supply water to stakeholders. Thus WUA’s runs all the supply scheme very smoothly and effectively with the cooperation of stakeholders. Dhamapur Lake’s present irrigation outreach capacity through its 2.20 km canal is 238 acres (96.32 ha) but presently 125 acres (50.6 ha) of farmland is irrigated. It is blissful with water all year. It is the best example of traditional water harvesting system constructed in a way to benefit local villages.

Dhamapur Lake was innovative in its ideas at the time of its construction

Near the spillway, there was an old method of irrigation, which used to be constructed using Rice straw as fibre, Mud as binding material, and the “Trunks of Bhedla mad” used as pipes. The villagers used to construct this water bund-wall locally known as “Bandh” with these pipes placed at different heights with the blocked waterside. They used to open up pipes from the top to discharge water in channels that run through villages supplying water. The channels ended at “Karli” river. Villagers used to open up pipes at the lower levels as the water level used to drop. Thus the earthen dam was constructed by using natural soil with minimum processing and was built with primitive equipment available at that time. Unlike modern concrete dams which require a sound foundation, this earthen dam was constructed to the adapted earth foundations. It is understood that the construction of the earth dam used simple operation and was done with the rule-of-thumb. The earth-fill was further protected by laterite stone pitching. This protected the earthen dam from erosion of the soil. This system was recently replaced by the steel gates with concrete walls. Formed by damming a valley with an earthen bank, it holds water in all the year-round.

Dhamapur Lake contributed to the evolution of efficient and contemporary engineering theories and practices

Design of Dhamapur Lake reflects geographical thoughtfulness. It is constructed between two hills of Dhamapur and Kalse Village. The site chosen at that time indicates the vision to provide natural irrigation and drinking water to both the villages. The irrigation is done through natural gravity as the villages are located at 4m. above MSL.  This dam and lake have contributed to the evolution of efficient and contemporary engineering theories and practices.

Dhamapur Lake is an example of attention to environmental aspects in its design and construction

Area of the zone of influence of Dhamapur Lake is 328.85 hectares out of which 21 % is forest, 72 % Agriculture, 5% Grassland and scrublands 2% rural settlements. It recharges water wells in villages of Dhamapur and Kalse. Dhamapur Lake testifies to the intimate knowledge that ancient villagers had of the local climate, soil properties, geology, hydrology and ecology. They also testify to their technical knowledge, evident in the sluice gates they built to control water flow. Water was channelized till 5 km till Hublichamal for irrigation by gravity through an earthen channel, known as Haran in the local language.

The dam site is surrounded by lush forest and high hills offer biodiversity. A report shows 134 plants species contain 34 herbs, 33 shrubs, 14 climbers, 42 trees, 3 orchids, species are reported as rare endangered species. As per international union for conservation of nature endemic spices of birds have been sighted on the lake. Apart from this smooth-coated otter, leopard, and wild boar barking dear, have also been known to inhabit the lake. The small population of otters inhabiting lake is of critical importance since they are considered to be an indicator of a healthy ecosystem. 39 butterflies’ species out of which Wax Dart Species reported 1st time in Maharashtra at Dhamapur Lake. Thus, a variety of spices, wildlife winter visitors can easily see on surrounding forests distinguishes Dhamapur from other dam bodies.

Dhamapur Lake was unique in some positive and constructive way

The lake is almost 500 years old and is still fully functional for its irrigation. Even when there was a severe drought in Maharashtra from 1973 to 1975, Dhamapur, Kalse and nearby villagers could use water for irrigation and drinking. Farmers continued their farming as usual even during this drought period. Numerous failures of poorly designed earth embankments have happened in the past. But this lake with its earthen dam is time-tested and has withstood even during the Koyna Earthquake in Dec 1967 having a magnitude of 6.3 on the Richter scale with an epicentre of about 200 km distance. Generally, it’s found that faults in the earth get activated due to the construction of a dam. But this Dhamapur lake-dam has not triggered such reservoir induced seismicity. Hence in last about 500 years, no such tectonic activity is registered in this district due to this dam. This lake has helped the nearby villages to be rich in agriculture and their livelihood over centuries. None of the farmers in these villages has committed suicide for the scarcity of water.

Dhamapur Lake bears the stamp of a cultural tradition or a civilization of past

Below mentioned is recorded in Gazetteer of the Bombay Presidency – vol X (Ratnagiri and Sawantwadi) published in 1880: - “Dhamapur lake has an area of 55 acres (22.26 ha), and a maximum depth of 37 ½ feet. Formed by damming a valley with an earthen bank, though the dam leaks considerably, it holds water all the year-round and shows no tendency to slit. It waters about 500 acres, 40 of the garden and the rest rice land.  Ancient Hemadpanthi style architecture temple “Bhagwati Mandir” was constructed on the top of the dam in 1531 on one side and the spillway to drain the overflow of water above the holding capacity of the dam is constructed on the other side.

Present State of Conservation

490 years old historical Dhamapur Lake constructed in the year 1530 is one of the finest Dams listed over India. As per the latest report of the National Wetland Atlas by SAC, ISRO, the area of Dhamapur Lake covers an area about 61.44 Ha. The Wetland Brief documentation details show the shrinking of Lake Area is a pertinent issue related to environmental degradation around the lake. Due to this, there is a threat to the potential of this ancient traditional water harvesting system. The first issue is destroying ecology and water pollution. As a dam is constructed by highly porous laterite stone, a large amount of water gets wasted through the dam body as well as foundation. Heavy leakages are observed throughout the year between Porous joints of laterite masonry. The Water Resource Department paying attention to this issue in the form of constructing a barrier structure like jacketing wall. The remedial work is in progress and some percentage of leakages can be spotted; a high amount of water gets wasted which could be used for several purposes.

Dhamapur Lake irrigates an area of 237 Ha every year with the left canal, right canal and backwaters of the lake, famous Konkan crop paddy grow in tank command which is a lifetime source of farmers and stakeholders. Farmers were demanding fully closed pipelines instead of an open canal to prevent water losses. The water Resource Department, paying attention to this issue, laid HDPE pipes for water supply.

The volume content of the lake, showing shrinking in the last few years, is an important point to note. As the dam is located in high rainfall zone and founded by lush forest, rainwater carries tremendous silt every year and it gets deposited in dam submergence. Also, residents behind dam submergence cause some misbehaves which threatens the dam. The digging and excavation processes have led to fissures in the laterite bedrocks, which may lead to percolation of the stored water and decrease the carrying capacity of Dhamapur Lake. As per one of the reports, the dead storage of the lake has almost filled with silt and approaching in live storage. Removal of accumulated silt from lake submergence will be the next activity. Very fertile silt can be useful for local farmers to use it in their farms.

The third issue is water pollution. The water from Dhamapur Lake is being used by human being for drinking purpose which adds serious threat to their health. If activities in Dhamapur Lake are limited to rowing, pedal boating then it would not be harmful to ecology. Another issue is about the immersion of Ganesh idols in Dhamapur Lake. There is no one to monitor the people who immerse the idols. Artificial water tanks could be formed on banks of the lake to immerse idols keeping intact the purity of the Dhamapur lake water. Hence, such a beautiful dam lake surrounding should be preserved, conserved from various threats to keep such ancient, historical structure lifelong.