African Experiences

Colin Hammond – 9th January 2007

A large audience provided a warm welcome for the return of Colin Hammond, who last spoke to us in November 2005 on theconstruction of the Ardingly Reservoir. Now recently retired, Colin was for many years a Consultant Civil and Water Engineer, involved in projects worldwide. The present talk. was to describe experiences in Uganda during the 1970’s, both in engineering and on safari.

Colin joined a United Nations and World Health Organisation project to update the water and sewerage facilities of Kampala and Jinja, that dated fom the 1920s, taking water trom Lake Victoria and returning the excess water and sewerage, following suitable treatment. The planning was laid out in three reports dealing with:

(1) The Immediate Needs 1969 to 1974,
(2) Stage 1 1974 to 1980 and
(3) 1980 to 2000.

Supportive studies were undertaken on leakage, water quality, Lake Victoria, groundwater and soil, local manufacture, water treatment, water stabilisation ponds, and finance.

Census studies showed the population to be approx. 350,000 in 1968 and projected to rise to 1.5 million by the year 2000. To more accurately estimate demand, population type and distribution were studied. The estimated average water demand was 180 litres per head per day (lhpd). This figure covered a wide variation, trom the rich with a western type of water supply of 500 lhpd, to the poor, who took water from standpipes, streams, springs and swamps, averaging 10 lhpd.

Plans and photographs were shown of the water works at Kampala, covering approx. 75 sq. miles and rising to 400ft. The terrain was mainly rock, on which the water treatment complex was built. The raw water was screened and filtered to reduce larvae and solids, then treated with chlorine for purification. The treatment complex included pressure filters, a pump house, and clear water tanks.

For the first report, to 1974, the needs included a capacity of 14 mill.ga1l/day, fine and coarse screens and a low level alarm, a fifth microstrainer, increased raw water and treated water pump efficiencies, increased chlorine storage capacity and the construction of labyrinths and dams in the clear water tanks to permit the 30 minute contact time with chlorine to ensure purification. At the request of the World Bank. an additional report was drawn up on the up-rating of a11 filters.

The second report, 1974 to 1980 forecast a capacity increase to 20 mill.gall/day. To accommodate this, provision was made to increase strainer capacity in the event of deterioration of raw water ftom Lake Victoria. All filters would need to be up-rated and chlorine capacity increased to 90 days supply. Attention would be required to the pumps, involving improvement and replacement. Additional pipelines would be required to meet increased transmission needs.

The third report, 1980 to 2000 forecast an increased capacity of 26 mill.gall/day. The building of five new rapid gravity filters was planned, as was the construction of a fifth Clearwater tank.

During this time of water engineering activity, there also was time for relaxation Safaris were undertaken. The first was to Murchison Falls Nationa1 Park. Spectacular pictures were shown of the Falls themselves in addition to the plentiful wildlife such as the Ugandan kob, oribi and elephants. Crocodiles were photographed during a river trip. The second safari was to Kidepi where there was plenty of game. Lions were photographed, on the ground and in trees. A leopard was seen but ran off quickly.

All present enjoyed a good lecture, with many excellent colour slides. Our President, Richard Norton proposed the vote of thanks.

C Harrison