The Gond dynasties mainly flourished in the Central highlands of India. This region includes Sagar, Bhopal, and nearly half of Narmada valley, including the flanks of Vindhya and the Satpuda mountain ranges of southern Madhya Pradesh. The principal states of the Gonds were Garha-Mandla (1300 to 1789), Devgarh, Kherla and Chanda. Besides these, there were also a few small princely states that existed until 1947 such as Makadai, Kavardha, Raigarh, Saranggarh and Sakti. The Garha-Mandla dynasty was the most majestic, and the most illustrious rulers of this dynasty were Sangramshah and the iconic queen Durgavati.
Water management in the Gond period
How did these dynasties manage their water needs? A peek into history reveals that while the names and descriptions of the ancient tanks and stepwells that existed during this period are available, very little information exists on the water science behind construction of these ancient tanks/step-wells.
Evidence shows that these dynasties managed their water based on a scientific understanding of the water resources available in the area. Water in those times was mainly stored in tanks as stand-alone tanks or a chain of tanks. Many of these tanks and stepwells exist even today and have been found to be nearly 500 years old. They have been constructed on suitable geological formations, built on gentle to moderate slopes or across small drainage lines.
Many of the tanks and step-wells constructed during that period are still in a good condition. One of the important technological peculiarities of the tanks is the way in which the storage capacity of the tank is designed and the surplus water is released from the waste -weir.
Classification of tanks
The tanks can be classified into:
Storage tanks – These tanks have an impervious bed and side walls and are perennial in nature because the main source of their water is rainfall while the contribution of ground water is negligible.
Recharge / Percolation tanks – These tanks have mostly been constructed on weathered granite (pervious formation). They have optimum depth and are linked to the local ground water table. They get filled due to run-off and the release of groundwater.
Chain of tanks – These are storage and or recharge tanks constructed along the same drainage line that meets different formations and slopes. Example – Maharajtal, Kolatal, Deotal, Supatal and Gangasagar.
Principle features of the tanks and step wells
Tanks
The tanks from the Gond period have earthen bunds with stone pitching. They are generally small, deep and their shape is mostly semi-circular or is determined based on the local topography. It is interesting to note that the chain of tanks store more water than stand alone single tanks.
The chain ensures removal of silt deposition and impurities, imparting them a long life, and ensures water availability in larger areas while their perennial nature ensures rich biodiversity. Since the recharge tanks are perennial, they support non-monsoon flows of rivers/streams. The Gonds did not use main streams for building chains/big dams. The focus was on construction of many small but deep tanks utilising small catchments.
Step-wells
The step-wells have been constructed on commercial routes and are deep enough to ensure water in summer and during droughts. Shah Nala is one such stepwell.
This beautiful step-well is situated on Narmada road and is also known as Kamli Wale Baba or Khuni Jalalshah step-well. It is looked after by saints of the local Muslim community. It is octagonal in shape and is very well protected. Steps are provided to reach the water at the bottom of the well. Stone blocks with lime-mortar have been used in the construction of this stepwell and the approximate depth of the step well is 102 feet. It is founded on weathered granite (thickness nearly 10 feet) with the bottom provided with a well of smaller diameter. The step-well is perennial and it still continues to overflow in the rainy season.
Pecularities of the water storage structures
The tank sizes vary across periods
The construction of water storage structures can be traced from the Ashoka period to Raja Bhoj (1011-1055) to Chandela (10th century to 13th century) to Bundela (15th century to 18th century) and the Gond period (1300 to 1789). In Parmar period, the tank at Bhojpur (water spread area 650 sq. Km.) on the river Betwa was constructed. Another tank at Bhopal, (water spread area 6.5 sq. Km.) was constructed on Kolansh river to feed tank at Bhojpur. During Chandela period, size of tanks reduced and smaller tanks were constructed. During Bundela period, tank size increased and large tanks were also built. In Gond period, the size of the tanks again reduced.
Chain tanks were common
The first known evidence of chain of tanks is from Sanchi, Madhya Pradesh. Three tanks exist on the hill slope and are said to be constructed during Ashoka period (Sanchi Hill). Other evidences are found in Chandela-Bundela period (Bundelkhand) and also in the Gond period.
Local material such as stones were used to construct tanks
During Parmar period, cementing material was not used. Instead, large and very heavily dressed stones were used and arranged one over the other. This arrangement, denied entry of rain water, reduced chances of weathering and ensured long life to the bunds. In Bundela-Chandela period, lime mortars were used as cementing material. Gonds also used lime mortar as cementing material. Inspite of the fact that cement was discovered, Gonds did not use cement.
The photograph given below shows the face of earthen bund and waste-weir of Sangram sagar, Jabalpur. Lime morter has been used in construction of waste-weir.
What can we learn from our ancestors
The Gonds understood the water bearing properties of geological formations (geological control) and utilised this understanding in selection of the sites for tanks and step-wells. Majority (58 percent) of the tanks that exist today from the Gond period are storage tanks and were built on impervious alluvial soil. Of these, twenty tanks are recharge tanks. Of these, thirteen recharge tanks are built on porous and permeable weathered granite, six are built on porous and semi-permeable sandstone and only one tank has been constructed on less permeable Lameta formation.
All the tanks were built based on sound engineering, which can be seen from the construction of waste-weir that continues to demonstrate exemplary silt disposal mechanism and is capable of negotiating surplus run-off. Bund width is adequate to withstand the water thrust at Full Tank Level. Local weather and the water bearing properties of the geological formations were also precisely known during those times. Capable and experienced masons were employed for the construction. Matchless combination between purpose, facilities and intention existed which was used to plan the appropriate sizes and number of water bodies. Need based construction of tanks ensured universal availability of water in the region. The tanks still continue to provide water even today in Garha area, Jabalpur.
This indigenous water wisdom of Gonds, particularly the relation between storage capacity and disposal of run-off from waste-weir is relevant even today and needs to be highlighted and discussed on scientific platforms and adopted in maintenance of modern ponds, tanks and reservoirs.
K. G, Vyas is a geologist and well known writer on environmental issues. He has served as a consultant for the Rajiv Gandhi Drinking Water Mission in Madhya Pradesh.