The 'Koop', a simple mechanical device, was introduced in the hilly terrains of Uttaranchal to tap potable drinking water from natural streams and rivers. It is a good example of adapting cost-effective and appropriate technology for specific local needs. The use of the Koop has improved availability and quality of drinking water apart, as it is easy to install, operate and maintain.
Uttaranchal is a state of natural beauty, with a total area of 51,125 sq km and a population of 8.48 million (Census 2001). The largest cities of the state are Dehradun (530,263), Hardwar (91,58,896) and Roorkee (115,278).
Traditionally, natural springs and gadheras (streams and rivers) served as major sources of water in hilly areas. Water from springs can be used for direct supply. Due to low discharge from springs, surface water from small streams was used for drinking purposes by diverting the supply main. This was done by constructing a cross wall across the stream against the flow, called Boulder-Filled Gallery (BFG). Construction of BFGs required expert supervision, huge quantities of raw materials which are not easily available at the source, and enormous operation and maintenance costs. To overcome these problems, Uttaranchal Koop was designed to replace BFGs, which are appropriate, reliable and cost effective.

	Rural area	Urban area
Gravity schemes	9,977	47
Pumping schemes	280	16
Total schemes	10,257	63

There were several problems experienced by the Uttaranchal Jal Sansthan with respect to the operation and maintenance of BFGs and the quality of water tapped from them. There were no arrangements for turbidity removal in BFGs. Thus, water supplied during monsoon was muddy and turbid. At times, during heavy floods, the cross walls of BFGs got damaged and washed away completely, and pipelines got choked resulting in silting inside the clear water reservoir (CWR). More resources (finance and manpower) were required for the restoration, repairs, de-silting of BFGs and removal of chokes after every monsoon. Due to these reasons, the water-supply schemes remained non-functional for several months. Intermittent water supply caused serious inconvenience to the public.
The Uttaranchal Koop, also known as 'French Well', is an innovation based on a riverbank filtration technique which obtains water from aquifers (layers of sand and gravel) near the riverbanks. An Uttaranchal Koop is a hollow cylindrical steel pipe with radial perforated pipes, connected with welded outlet socket in the middle of a vertical cylinder. A 1–1.5 m long pipe is placed vertically 3 to 4 m below the bed of the stream with the open end at the bottom and closed end at the top.

The device is placed over the impermeable strata of streams tapping the entire alluvial field. After placing the Koop, the space-graded filter media envelops the Koop up to the natural bed level of the stream. The base flow of the stream rises inside the cylindrical pipe through its open end and perforated radial pipes due to hydrostatic pressure of the submerged surface, and maintains a static level in the cylindrical pipe. The outlet socket, placed almost at the middle of the Koop, is connected to the 'gravity-main' of the water supply scheme. The gravity main starts drawing water from the Koop. The static level of the well is maintained through hydrostatic pressure, ensuring a continuous flow.

The Koop is designed in such a way that it works even during minimum discharge i.e., during summers and winters. Uttaranchal Koops are being used successfully in 1,019 rural water supply schemes and 58 urban water supply schemes in Uttaranchal. The combination of each Uttaranchal Koop costs little more than Rs. 30,000. Detailed work-wise cost estimations are given in the table below:

Turbidity, suspended particles and coliform are removed to a great extent by the natural streambed filtration process involved in the use of the Uttaranchal Koop. The total coliform and faecal coliform levels in the water drawn from gadhera (total coliform: 315 mpn/100 ml, faecal coliform: 180 mpn/100 ml) are on the higher side when compared to the water from Uttaranchal Koop (total coliform: 41 mpn/100 ml, faecal coliform: 25 mpn/100 ml). Apart from lower levels of coliform, the Koop structure is less likely to be damaged during the monsoon, and less open to tampering by miscreants.

Cost Estimation of Uttaranchal Koop (in Rs.)

Work Description	Amount
(i) In soil mixed boulder 12.95 m3 @ 54.05 m3	700
(ii) In medium rock 5.55 m3 @ 130.25/m3	723
(iii) Extra for lifting excavation earth below 1.5 m depth	100
(iv) Dewatering including cartage of pumps, oil lubricants, labor etc. complete or stream (gadhera) diversion work	5,000
(v) Fixing of shuttering including its cartage, rent and wastage	2,500
(vi) Supply and filling filter media 18.5 cum @ 350/cum	6,475
(vii) Cartage of filter media (Coarse sand)	12,210
(viii) Cost of Uttaranchal Koop as per type design (250 mm dia)	3,360
(ix) Carting and fixing of Uttaranchal Koop	2,000
Total	33,068

The estimated cost of construction of the BFG (approx. 4 m wide) and roughening filter is around Rs. 1,75,395 per unit, whereas the total cost of fixing the Uttaranchal Koop below the river bed (2 to 3 m depth), including all the excavations charges, supply and filling of filter media etc., is only Rs. 33,000. The capital cost of fixing Uttaranchal Koop is around 15% of the cost of BFG, while its maintenance cost is around 1% of BFG. There is a cost saving of Rs. 1.34 lakhs by using Uttaranchal Koop in place of a BFG and roughening filter.
The Uttaranchal Koop provides a significant improvement in the quality and quantity of water available in rural areas while costing far less than traditional approaches. Uttaranchal Koops are simple to install and operate, almost maintenance free, economical and sustainable. They are easily replicable in hilly areas of the country.

For further details, contact:

Mr. H. P. Uniyal
General Manager
Uttaranchal Jal Sansthan
Jalbhawan, B-block
Nehru Colony, Dehradun - 248 001