New technology can curb water shortage in towns

The curse of perennial water problems in major towns in the country could be a thing of the past if a new technique that uses modern weather prediction to fine-tune water supplies is adopted.

Currently, Nairobi residents are suffering the effects of water rationing after Nairobi City Water and Sewerage Company (NCWSC) commenced water rationing in the city on January 1.

The rationing was due to a fall in water levels at Ndakaini dam, a major water reservoir for the city, to a capacity of 47 per cent which is below the required levels. The rationing is expected to last for about four months when long rains are expected.

But there lies an innovative way that can be used to save these residents in future from such suffering.

Forecast Informed Reservoir Operations (Firo), is a water management tool that uses advances in weather forecasting as a cheap and effective way to keep vital reservoirs full while also boosting flood protection.

The technique in use on Lake Mendocino in California, in the US, uses data from watershed monitoring and modern weather and water forecasting to help water managers selectively retain or release water from reservoirs in a manner that reflects current and forecasted conditions.

The decision to release water under this technique also considers weather observations and predictions and the current watershed conditions, which, in some cases, would indicate greater drawdown for flood risk reduction so long as there is confidence that the amount of precipitation and runoff will restore reservoir levels for water supply after the storm.

During storms — brought about by long periods of rain causing moderate-to-high reservoir levels — the technique releases water to re-establish flood control space.

This is done with the future in focus where some of that water is retained for future supply as long as no major precipitation is predicted for several days.

If NCWSC can adopt this system in collaboration with the Kenya Meteorological Department (KMD), then the water problems facing the over 3 million Nairobi residents could be nipped in the bud.

Currently, the water company is experiencing a daily shortfall of over 214 cubic metres of water with daily demand of 760,000 cubic metres — way above its current production which is at 545,034 cubic metres a day.

To makes matters worse, KMD deputy director Mr Sammy Mwangi in an interview with the Nation in December, indicated that Kenya is currently witnessing two kinds of drought – hydrological and agricultural – both of which are disastrous as water and food have become scarce.

“We had a near total rainfall failure in the months of March and April 2016 and farmers did not produce enough food. The late rainfall is an indicator of a poor harvesting season ahead, so we should prepare for food and pasture shortage,” said Mwangi then.

He further added that rains are not expected until April which does not make matters good for the millions of residents having to miss out on an essential service like water.