ABSTRACT.

TITLE.  EL NINO AND LA NINA EFFECT ON IRRIGATION WATER SUPPLY.

Author: Mr. Z. Rahaman

As a consequence of population growth and development of more arable land for agriculture it became necessary to ensure a stable supply of irrigation water through the planting seasons that would improve food security, production and economic growth. Thus the creation of the East Demerara Water Conservancy was to fulfill a need to withstand the adverse variations in climate in order to maintain an adequate supply of water resource in times of need.

This paper examines the rainfall and water level data taken at Lama, in the East Demerara Water Conservancy, over a twenty year period from 1979 to 1999. The months considered in the data set – September to April, particularly to highlight the effects of the El Nino and La Nina phenomena on the variation of rainfall , one of the primary sources of inputand water levela measure of storage of this man made reservoir.

An examination will be made of anomalies of these parameters, the variation in severity of occurrences and their impacts on the resource capability of this Conservancy.

ABSTRACT.

AUTHOR: Mr. K. Simon, Sp. Met. (c)

TITLE.  The El Nino / La Nina and Southern Oscillation, Impacts Mitigation and Information Dissemination.

Reviewed are observations and theories of ENSO, its teleconnections and its impacts on countries around the world including Guyana. Mitigation measures are considered. Precipitation classifications for effective communication with users are justified and extended. Categorisation of the effects of the precipitation is introduced and so is the long-term forecast model that relates to the precipitation classifications. The Hydrometeorological Service's forecast assessment method is improved and a limited test of the forecast has yielded satisfactorily results.

ENSO has significant global impacts and its frequency and intensity have been increasing in recent times, but mitigation measures have been useful in a number of countries. Mitigation measures can yield increased benefits if the relevant research is done and shared. A co-ordinated approach involving several agencies and professionals is recommended and so are sustainable development strategies.  The achievement of the objectives is likely to be considered by the limited availability of technical resources.

ABSTRACT.

AUTHOR: Mrs. J. Jafferally, Sp. Hyd (sw).

TITLE. The Effects of El Nino on Hydrology.

The El Nino phenomenon is one which causes extreme weather conditions to be experienced. This event is usually signaled by the large increase in sea surface temperatures in the eastern and central tropical Pacific Ocean. These warm waters are the forerunners to abnormal air pressure patterns, abnormal patterns of rainfall and sometimes a complete shut down of the normal easterly winds across the entire tropical Pacific.
This event brings to the fore such activities as drought, brush fires, etc. These and other activities cause great hardship on communities and countries globally.

The impact of the 1997-1998 event was greatly felt in Guyana because one aspect was the severe drought experienced. The availability of water in our hinterland areas was very scarce. This paper attempts to look into the effects of the event on one element of the hydrological process - surface flow. It is shown that decreased rainfall resulting from the El Nino phenomenon resulted in surface flow to be below the normal supply in some rivers. It will also be seen that when the effects of El Nino are minimized surface flows were in excess of the normal capacity. An attempt will also be made to develop a forecasting tool to estimate discharges in the Mazaruni and Demerara rivers during the El Nino period.