The Himalayas though considered as the 'Water tower of Asia' have the perennial problem of drinking water on their towering ridges and slopes. The valleys are fortunate because surface or the subsurface water from the heights moves down to the valleys. Since times immemorial the springs have been the mainstay of water supply in the mountainous regions. It is said that when Kalyan Chand, a king of Chand dynasty shifted his capital from Champawat to Almora in 1560, apart from the strategic location, availability of potable water in plenty at the ridge top was one of the important criterion. Yes Almora then had 360 flowing springs. Alas, now only handfuls are remaining and they too generally go dry in the peak summers.
Where have the springs vanished? People blame the climate change. Well the climate has been changing for the past thousands of years, whereas at least 80 springs were flowing in the early sixties in Almora and people were using them freely. Where have they vanished! Climate change is not like an on-off switch. It is a slow and a gradual process. Then what could be the reason.
How and why the behavior of a spring changes was bugging the minds of the scientists at G.B. Pant University of Agriculture and Technology at Pant Nagar, Uttarakhand. A.K. Vashisht and H.C. Sharma, scientists carried out studies on the hydrological behavior of springs and published their findings recently in the Current Science. Their study becomes interesting and significant now at a time when the newly formed state of Uttarakhand is facing the drinking water crunch. At Almora for example the available drinking water supply is 5 million liters daily (MLD), whereas the requirement is around 10 MLD. The requirement has tremendously increased because of the population pressure. More population means more dwellings. For which land is required and of course the trees are hacked to make clearings. All these human activities affect the springs.
Springs and 'naulas' are two types of subsurface water occurrences in the Himalayas. Naulas are usually one to two metres deep, often lined pits where water seeps in and accumulates. Springs on the other hand are termed as 'Dhara', where a stream of water flows out. In remote rural areas naulas and springs are still a major source of drinking water. Vashisht in his paper quotes a study which says that 72% women and 14% children of the Hiamalaya have to bear the major responsibility of carrying potable water. On an average 60% of the womenfolk have to walk ? a km and another 10% have to trudge 4 km to fetch water for the family.
Though one of the major source of drinking water, the springs are in sheer neglect now. They face the brunt of the human activities and nature's ire too. The springs are drying up and or becoming seasonal. The springs are not merely a source of potable water for us they are also one of the major contributors for the streams in the valleys. The reduced or negligible discharge from the springs has put the streams and the rivers under great stress. The difference in the volume of water flowing down the rivers during dry and rainy seasons is continuously increasing and in some cases it is more than 1000 times says Vashisht. The irregular supply from the springs is also a cause of too little and too much water syndrome-a common feature of a desert terrain. Erratic rainfall, construction activity over springs/catchments of the springs and hacking of trees are the three main reasons for drying of the springs.
Normally the soil on the hill slopes remains undisturbed and acts as a sponge during the monsoons. Water travels as rills down the slope and a major part of it enters the depths of the strata. Subsurface water flows under gravity through the joints and fissures of the rocks or porous sediments. Upon meeting an impermeable surface it oozes out at the surface as a spring. Hacked trees, mining activities, road construction, deforestation, excess grazing by the live stock leads to erosion of top soil and reduce the spongy action of the top soil. Thus water falling on the slopes is lost as a run off. This also leads to more velocity of the water and it augments the surface erosion. More erosion leads to landslides and in case a habitation is threatened then naturally civil engineering techniques are used to save the habitation. These amounts to diverting the run off water thereby reducing the availability of rain water for the recharge of the springs.
The climate patterns are changing. Rain fall is gradually being reduced. Thus the annual availability of water for recharge is much reduced. A study of historical background of springs in Almora area says that over a period of 150 years out 360 flowing springs now only 60 remain. It is imperative that annual rainfall can not be augmented but at least ways can be developed to make available whatever water falls on the surface towards the recharge of the springs. In addition in case of excess discharge the spring water has to be controlled to minimize the run-off.
Both situations that is a drying spring or an over flowing spring need to be managed to obtain the maximum advantage. This management is site specific. In order to know the behavior of the spring over a period of time a hydrograph is prepared. Vashisht observes that fluctuation of spring discharge is due to variations in the rate of recharge and prevailing hydrologic and geologic conditions. These two seldom vary frequently. Hence the factor which controls the discharge of the spring most is the rainfall.
In order to prove their contention Vashisht and his colleague studied a spring for eight years from 1999 to 2006 and analyzed the time lag period between rainfall and consequent increase in spring discharge. They found that water from the remotest source of recharge reached the outlet in 57 days.
This is a significant find, because such kind of study had not been undertaken earlier. This type of study is time consuming because it is based on prolonged observations for a number of years. A lot depends upon the land-use patterns too. If the recharge area is disturbed by construction activity or concretized the recharge will go haywire. There is a dire need to identify all potential springs and work out the details of their catchments, time lag between recharge and consequent augmentation of discharge etc. Thereafter the local authorities can top any activity that is likely to affect the recharge process.
With the changing climates and more spells of droughts water scarcity is likely to hit all the mountain terrains. The towns located on the ridges are going to be the worst affected. It is time that the society and the government recognize the significance and utility of springs as a source of fresh water and conserves them.