WATER SCARCITY INSPIRES INNOVATIVE WAYS OF GROUNDWATER HARVESTING

By Bob Koigi

A burgeoning population and increasing agriculture and industrial activities in the recent past have put a strain on water availability with the demand in households, farms and factories reaching unprecedented levels. In Nairobi alone demand is now at 570 million litres of water by and is expected to rise to 1.2 billion litres in 2035 studies show.

The startling figures could trigger water woes as residents compete for one of the most vital yet limited resources for human survival.

Increased urbanization, combined with the effects of climate change is proving an unsustainable combination, experts say.

Water demand has grown tremendously grown beyond homes to institutions including schools, hospitals and industries as lifestyles, increased enrollments in schools, a boom in healthcare that has seen an increase in the number of health institutions and new treatment models and emergence of new industries put a strain on what currently exists.

Agriculture which is perhaps the largest consumer of water has seen food producers embrace innovative ways that guarantee year-round harvests as rainfall increasingly become scarce. It is a phenomenon that has been embraced by both small and large scale farmers. Farrow or what is christened flooding watering method continues to gain traction among smallholder keen on irrigation despite its huge water use which has further put a strain on water availability.

Yet despite Kenya being one of the most water scarce country world over, the country is among those listed as wasting the most water, with urban population leading the pack through activities like flushing toilets, leaving tap water running among others.

Now experts are vouching for water harvesting techniques as the sure bet to saving the country from acute water shortage.But even as the rain pours, the country is beset with warnings that as soon as the rain stops we shall return to water shortages. In Nairobi, the tap water rationing still continues. The problem according to the United Nations Environment Programme, (UNEP) is not the rain, but the water waste. If the country harvested the rainfall, we would have plenty of water, and water harvesting isn’t even expensive.

Kenya’s groundwater on the other hand which constitutes on average five per cent of the nation’s  renewable resources offers plausible alternatives.

More Kenyans are running out water source options,with traditional water sources experiencing dwindling supplies. Majority of Kenyans are instead are turning to borehole water.

To meet this burgeoning water demands there has been a proliferation numerous companies have come up to offer borehole drilling services while utilizing the latest borehole drilling technology and machinery. The companies have a clientele base that span individuals, corporate, communities, NGOS, government institutions, as well as private and public institutions.

Types of boreholes

Mostly the type of borehole depends on the specific intended use, and the preferred size by the customer. Water from some of the commonly sunk water wells will serve commercial purposes, industrial use, irrigation, general agricultural practice, and domestic purposes among other uses. In terms of size, the diameter of the well can range from around 3.5 feet to about 13 feet in diameter. Many firms can also handle depths of up to 600metres depending on the specific level of water along with other  considerations and preferences.

Qualities of a good borehole

The entire purpose of drilling a borehole is to source for water therefore a good borehole should deliver what is deemed borehole yield, the volume of water that can be abstracted from a borehole. It is of utmost importance to ensure one does not over pump the borehole in order not to induce saline intrusion, encrustation, excess lowering of the water table or piezometric surface or borehole failure.

Factors to consider in selecting a good borehole

A borehole is an expensive investment. Good construction is therefore crucial.

The first step in successfully constructing a borehole is knowing what you want. How much water do you need and what will you use it for? Irrigation? Domestic supply?

This will affect the water quality required. If you need water for toilet flushing and sanitation, for example, a low-yielding borehole with saline water will be sufficient. But it will be of no use if you require high quality water for crop irrigation.

Check with others to see who has a borehole before constructing a borehole. If they do, what is the quality like and what is the yield? This will give you an idea of your chances of finding water. Also consult a geologist or  hydrogeologist (groundwater specialist) with experience in the region where you farm

He will be able to tell you immediately, before any detailed assessment is done, if you’re likely to get a highyielding borehole of 5l/s or more, or a low-yielding borehole (less than 1l/s).

Drilling water policies

The underwater drilling water policies and regulations are meant to protect the water ecosystem from overexploitation. According to the fourth schedule of the Water Act 2002 requires that a person constructing a borehole should give notice of his intention to the Water Resource Management Authority and shall comply with such requirements as may be imposed by the Authority, WRMA.

They are also required to keep records of borehole geological logs, water struck level, test pumping data and borehole yield, and upon completion of drilling be submitted to WRMA.

The person drilling the borehole is supposed to give the Authority’s officers unfettered access to the well for inspection, taking of samples and documenting.

The regulation also stipulates that boreholes must be at least 100 meters apart.

Before drilling a borehole, both a hydro-geological survey and an Environmental Impact Assessment test have to be carried out and the results submitted to the relevant authorities.

The hydro-geological survey is meant to determine availability of water below the ground and the depth at which water is likely to be struck. “Failure to carry out a thorough due diligence can cause a number of problems to the aquifer the borehole will tap from. Due diligence involves making sure that the material used to construct the borehole will not for example contaminate the surrounding area.It is important to involve hydrogeologists who design and carry out tests that make sure the borehole performs as expected,” said Davis & Shirtliff CEO David Gatende in a past interview

Those who have invested in boreholes have enjoyed their investments.

Daniel Juma, of Joska Township on Nairobi’s outskirts is one of the thousands of residents who have found a new lifeline in borehole water which is becoming common in Nairobi considering that up to 40 percent of the city’s population is not directly supplied with piped water. Even those with access to piped water often supplement their supply with borehole water or harvested rainwater because the piped supply is unreliable.

“I have never had a problem with water access for my family of seven since I invested in borehole drilling about two years ago. The piped water that I relied on previously was very intermittent and would only be available for two days in a week. I ended up spending too much money to buy water from vendors,” said Juma who now says he has managed to save 100 per cent on water-expenses with his water inspiring him to start a car-washing garage.

Derrick Juma a resident of Ruai has been in the business of horticulture farming for one year now after he lost his job. He invested part of his savings in drilling a borehole, an investment he has never regretted. “I noticed a gap in the market for fresh produce in schools and hotels around the area I reside in. I quickly did my calculations and decided to invest in greenhouse farming and have a borehole drilled. Water has never been a problem. I am now planning to expand my farming,” he said.

For large scale farms, the demand for water has been necessitated by the kind of crop they grow, predominantly the water guzzling horticulture produce and in most cases to meet their targeted market needs- since their produce is required in markets at specific times meaning water, a key input must be available throughout. With limited water resources, boreholes remains a viable option as water is guaranteed for a long time and owing to the size of the farms and the complicated food production processes, the water source should not be replenished quite often to avoid disrupting the farming cycle. The returns on investment that is accrued from drilling boreholes for these farms far outpaces any other water source.

With the cost of borehole drilling dipping considerably as new entrants join the business, and with the long term benefits associated with borehole water more Kenyans are finding a new lifeline in underground water.“Borehole water is the way to go owing to the huge demand of water which is becoming unsustainable. The only thing to consider is to embrace drilling in a sustainable manner to ensure sustainability in the long run,” said Maxwell Mutuku a water engineer.