0 Tracking Sources and Fate of Groundwater Nitrate in Kisumu City and Kano Plains, Kenya

Spatial distribution of the groundwater sampling points

Groundwater nitrate (NO₃⁻) pollution sources and in situ attenuation were investigated in Kisumu city and Kano plains. Samples from 62 groundwater wells consisting of shallow wells (hand dug, depth <10 m) and boreholes (machine drilled, depth >15 m) were obtained during wet (May–July 2017) and dry (February 2018) seasons and analyzed for physicochemical and isotopic (δ¹⁵N-NO₃⁻, δ¹⁸O-NO₃⁻, and δ¹¹B) parameters. Groundwater NO₃⁻ concentrations ranged from <0.04 to 90.6 mg L⁻¹. Boreholes in Ahero town showed significantly higher NO₃⁻ (20.0–70.0 mg L⁻¹) than boreholes in the Kano plains (<10.0 mg L⁻¹). Shallow wells in Kisumu gave significantly higher NO₃⁻ (11.4–90.6 mg L⁻¹) than those in the Kano plains (<10.0 mg L⁻¹). About 63% of the boreholes and 75% of the shallow wells exceeded the drinking water WHO threshold for NO₃⁻ and NO₂⁻ (nitrite) during the study period. Mean δ¹⁵N-NO₃⁻ values of 14.8‰ ± 7.0‰ and 20.7‰ ± 11.1‰, and δ¹⁸O-NO₃⁻ values of 10.2‰ ± 5.2‰ and 13.2‰ ± 6.0‰ in wet and dry seasons, respectively, indicated manure and/or sewage as main sources of groundwater NO₃⁻. However, a concurrent enrichment of δ¹⁵N and δ¹⁸O was observed, especially in the dry season, with a corresponding NO₃⁻ decrease, indicating in situ denitrification. In addition, partial nitrification of mostly sewage derived NH₄⁺ appeared to be responsible for increased NO₂⁻ concentrations observed in the dry season. Specifically, targeted δ¹¹B data indicated that sewage was the main source of groundwater NO₃⁻ pollution in shallow wells within Kisumu informal settlements, boreholes in Ahero, and public institutions in populated neighborhoods of Kano; while manure was the main source of NO₃⁻ in boreholes and shallow wells in the Kano and planned estates around Kisumu. Waste-water sanitation systems in the region should be urgently improved to avoid further deterioration of groundwater sources. View Full-Text or the Abstract

Keywords: Kenya; Kisumu; groundwater; nitrate; hydrochemistry; denitrification

0 Nairobi Water Fund: Securing Water from Tap to Tap

With Nairobi’s population growing at almost 3% annually and water availability decreasing more rapidly as a result of climate change, the city and its four million residents face a serious challenge. More than 90% of Nairobi’s water and at least 60% of its electricity come from the Tana River.

School boys enjoying spring water in Maragua
sub watershed. Photo: Fred Kihara

The Nature Conservancy (TNC), a global not-for-profit organization, is working with 18 public and private partners, including Coca-Cola, East African Breweries, KENGEN and the Water Resources Management Authority (WRMA), to proactively address Kenya’s water scarcity issues by bringing the Water Fund model to Kenya. Over the past 12 years TNC has worked with partners in Latin America to create 32 Water Funds that now help to conserve water sources for tens of millions of people. The Nairobi Water Fund, started in 2012, marks the first for Africa.

The Water Fund model engages large, downstream users, usually corporations and utilities, that willingly contribute to a water conservation fund as a way of shoring up their business investments. Revenues generated by the water conservation fund are then used to help pay for water-smart management practices, such as tree-planting and terracing, on upstream lands that filter and regulate the water supply. A healthy watershed reduces water treatment costs, minimizes water shortages and enhances communities’ ability to adapt to climate change.

For the Nairobi Water Fund, TNC has completed a feasibility study, launched pilot conservation projects in three priority watersheds – Maragua, Sagana and Thika- Chania, all of which are important for Nairobi’s water and power supplies – developed environmental and socio-economic monitoring programs and formed a high-powered Steering Committee.

Over the next five years, the goal is to capitalize Nairobi’s water conservation fund and increase watershed conservation upstream efforts to further reduce sedimentation and water treatment costs. As sedimentation decreases through improved land management practices, so too will water treatment costs, which allows organizations like WRMA and the International Center for Tropical Agriculture (CIAT) to channel more of their resources into efforts that improve treatment and distribution systems. Ultimately, the aim is to develop a replicable tool that can be used to ensure good water quality, adequate supply, lower treatment and distribution costs and reliable power in other parts of Africa.

Land owners implementing soil conservation measures in Upper Tana.
Photo credit: Fred Kihara

More information about Water Funds can be found in The Nature Conservancy’s Water Fund Manual or A Primer for Monitoring Water Funds

0 ‘Streams - Many smalls makes big’

This is a continuation of my previous post ‘Going going gone:…..’. Often, we tend to blame others, droughts, floods, bad omen or climate change for our environmental woes. But the fact is, most of environmental degradation is 'our own doing'. First, we need to take individual responsibility of our actions and also collective responsibility as a nation. The suggestions outlined here are collective, most of them on policy.

Allow me to correlate the wetlands and watersheds areas to roads. In our Kenyan Road Network, we have Class A Roads – linking Kenya to neighbouring countries. Class B Roads link major cities and towns. These two road classes are under the jurisdiction of the Ministry of Roads and Kenya National Highways Authority, for maintenance and infrastructural development. Others roads fall under the Kenya Rural Roads Authority and local government through municipals and town councils, as well as constituency funding. Correlating this road network to our wetlands and watersheds environments gives us the following: Major water towers (e.g. Mau  Complex, Mt. Kenya, Cherangani Hills, Mt. Elgon, Aberdare Ranges) and minor water towers, Big and small rivers and their catchments; Lakes, dams, swamps and marshes, springs and streams. As in the case of Class A and B roads, the major watersheds and rivers are taken care of the central government through the relevant ministries. Management of such environments requires an integrated approach that involves all stakeholders on the ground. Disparity comes in at the level of the local small rivers, springs and streams. Here, nobody seems to bother. While these are the ones that feed to the big rivers like Tana River for instance, hence being of great economic value to the nation, we only tend to see the Tana in our 'narrow' watershed management plans. We fail to see Rathithi stream, Gakui stream and Gakui spring for example, while they are the ones that recharge River Tana.

Apparently then, a river is not like a road, because if the feeder road is passable, we will still see traffic in the main, possibly tarmacked road. That does not apply with rivers. Reduced water in the stream directly means reduced volume in the main river in a direct relationship. We have to see it that way, in order to think and plan backwards.  Kenya is investing heavily on alternative electric power sources such as Geothermal and Wind Electric Power Production. Nevertheless, the country still relies heavily on Hydro-Electric Power (HEP) in its national grid and this is likely to be so for a long time to come. To get HEP, we need volume flowing through our rivers, and wisdom call us to protect the sources and tributaries of ALL rivers. Otherwise one day we wake up and darkness, factories and industries have to work half day, jobs and families are affected etc as power is rationed. Woe unto us if we think distributing free Energy Saving Bulbs can help us. Is it sustainable? That's like taking a pill for headache, heals the symptom alright, but the disease the root cause, is still there. I'd rather we use such funds to plant more trees and create awareness on the importance of protecting and conserving the watersheds.

How do we protect our springs, and the streams that the central government cannot take care of because of their apparent small size and ‘insignificance’? Over to you. I will be glad to hear about your local springs, streams and rivers...........and what local people are doing to save them!