STUDY OF GROUNDWATER RECHARGE TO THE KIKUYU SPRINGS
One of WRA’s key Strategic Objective is to “Improve the Protection of Water Resources within the country”. Based on this core function, WRA identifies and conserves groundwater resources under threat, amongst them, the Kikuyu Springs Aquifer. This Aquifer is a significant public water source in the northwest of Nairobi area and hence vital water supply for the Capital City, Nairobi.
Land use changes, encroachment of the Ondiri Swamp and escalating groundwater abstraction are a source of concern for the long-term sustainability of the Kikuyu Springs as a public water supply source. As a result of this, in 2011, WRA through Norken (I) Ltd., Engineering and Management Consultants carried out a study.
The objectives of this study were:-
- To define and map the area or areas which constitute the recharge zone or zones for the Kikuyu Springs aquifer.
- To quantify mean annual recharge to the recharge zone or zones, and describe parameters that are likely to lead to variation in natural recharge;
- To describe the measures that should be put in place to protect the recharge area or areas from destructive land uses
- To make recommendations as to whether the aquifer unit should be accorded “Special Aquifer” status in respect to the Water Resources Management Rules, 2007.
- To define the limits of a groundwater conservation area or areas that might be gazetted in order that the recharge areas or areas are protected in future.
What were the key findings of the study?
The Study showed that the Kikuyu Springs Aquifer extends over an area of 161 square kilometres, from Bathi Springs in the north to just beyond Nyakumu Swamp in the south.
Map 1. Proposed Groundwater Conservation Area (GCA) for the Kikuyu Springs Aquifer
It was noted that
- The main Kikuyu Springs recharge rock is in Limuru although groundwater infiltrates way down into the Karura and Kabete areas, which form the second of the two main aquifers.
- A clear recharge path is developed between Bathi Springs in the north, through Kikuyu Springs to Kerarapon Springs south of the aquifer.
- The total annual recharge amounts to 13.2 Million Cubic Meters (MCM) against an abstraction of 6.7 MCM from boreholes and 2.3 MCM abstracted from Kikuyu Springs discharge. Up to 68% of the annual recharge is abstracted, which should raise concern in view of the lack of a Reserve declared for the aquifer.
- Abstraction in the northern zone will have more impact on the system than abstraction in the lower zone around Ondiri swamp and Kikuyu springs and should be regulated.
The study finally recommended that;
- Alternative water supply sources for the settlements in the main recharge zones of the aquifer are investigated.
- The recharge areas must be protected against degradation.
- A Reserve volume should be declared for the Kikuyu Springs Aquifer to regulate the amount of water being abstracted
Kikuyu Springs Aquifer Draft Groundwater Management Guidelines
WRA prepared the draft Management Guidelines after extensive stakeholder consultations from the proposed Groundwater Conservation Area (GCA), including water users, area Members of Parliament, Members of County Assembly and other institutions. The GCA is established in accordance with the Water Act (2002) and the Water Resources Management Rules, 2007 (with amendments in 2012).
The Water Resources Management Rules, 2007 outline the process of identifying areas to be designated as groundwater protection and conservation areas. Part XI Rule 123(1) states that:
Pursuant to Sections 17 and 44 of the Act (Water Act 2002), the Authority may identify a catchment area, part of a catchment area or water resource to be identified as areas to be protected or designated as groundwater conservation areas if the Authority is satisfied that doing so is necessary for the protection of the water resource and its multiple uses.
Part D of the Sixth Schedule sets out the contents of management rules or plans related to a protected area or groundwater conservation area and may include:
Procedures to be applied for the management of the Protected Area or Groundwater Conservation Area;
The objective of the GCA guidelines is to provide a framework under which groundwater use within the conservation area will be undertaken in a manner such that the desired future condition of the resource is fulfilled.
Consequently, the desired future condition of the GCA is summarized as follows:
- Groundwater quality remains potable by Kenyan Standards (KEBS: KS 05-459: Part 1: 1996);
- Annual renewable groundwater recharge is sustained at or over the year 2012 level, subject to climate change effects;
- Annual groundwater abstraction does not exceed 70% of the total aquifer recharge.
- Artesian pressure is maintained at a level that can sustain Ondiri Swamp and Kikuyu Springs.
- Other groundwater dependent ecosystems, here identified as wetlands, are protected.
WRA Achievements in regards to the gazettement of the Kikuyu Springs;
A gazette notice was published on the local dailies on 12th June, 2013 with the aim of gazetting the Kikuyu Springs recharge areas as a groundwater protection zone and groundwater conservation areas. This raised a number of concerns from the public which required further clarification on the meaning and implications of gazettement to the communities living in the delineated areas proposed for gazettement.
A series of sensitization and consultative meetings have been held since then;
3 community sensitization meetings were held through Onkaru, Gitangu Gitathuro and Mweteta Water Resources Users Associations (WRUAs) between August and October 2013
On 14th March 2014 WRA held a consultative forum with key stakeholders at Wida Highway Motel
2 sensitization meetings were held between WRA and MCAs for Kikuyu, Lari, Kabete and Limuru Sub-County on September and October 2014
A consultative meeting between WRA and Kiambu Members of Parliament was held on 3rd December 2014 at the Intercontinental Hotel, where the MPs requested WRA to develop the Management Guidelines to be discussed with all involved stakeholders before the actual gazettement process takes place
A consultative meeting between WRA, the MCAs and CECs from County Government of Kiambu was held on 17th January 2017 at the Kilimo Grand Resort Hotel, Thogoto
A three-day meeting shall be held in 31st January to 2nd February 2017 between WRA and a great number of stakeholders in order to extensively sensitize and exploit any issues before the actual gazettement. This meeting is also meant to adopt the draft Management Guidelines to be followed one the gazettement of the area is done.
Ground Water Recharge Area- Ground Water Recharge Area is a hydrological process where water moves downward from surface water to groundwater. It is the main method through which water enters an aquifer.
Water Abstraction- This is the process by which water in its natural environment may be artificially removed for use in irrigation, commercial use or domestic use.