Hydrology Division is a specialized branch of the Irrigation Department which is responsible for maintaining hydro-meteorological information system of the country. It was formed, as a separate division under the Irrigation Engineer Shirley J. Bocks, in late 1940s, nearly 50 years after the formation of Irrigation Department. However collection of hydro-meteorological data in major river basins had been started few decades back. River gauge at ‘Nagalagam Street’ on Kelani River is functioning from 1924.
Hydrology Division is functioning under the Director of Irrigation (Hydrology) who is responsible for Administration, Financial Control and Management of Hydro-meteorological Information System of the country.
There are two Chief Engineers (CEE) working under the Director (Hydrology). One is assigned with the responsibility of management of Hydro-meteorological Observation Network, which comprises of 33 principal stations, 33 peripheral stations 18 rainfall stations and 4 Weather Stations. At present there are about 10 Hydrological Field Assistants and 110 Hydrological Survey Helpers to assist him in the process of data collection. The other CE is assigned with the responsibility of management of ‘Hydro-meteorological Data Processing Unit’ which includes Processing, Archiving and Dissemination of data and information to Irrigation Department and outside agencies on their request. There are 10 Hydrological Assistants to assist him in processing data.
In addition to that there are two engineers to assist hydrological studies in new & existing irrigation schemes and river modeling & flood forecasting relevant to major rivers.
Administration unit comprises of three Management Assistants, Draftsperson, Drivers etc are directly functioning under the Director Hydrology.
Main Responsibilities and Functions
Responsibilities and functions of Hydrology Division are mentioned below.
- Management of island wide hydro-meteorological observation network including adding or removing stations as per the requirements and priorities.
- Management of hydro-meteorological database and information system with necessary improvements to meet the present and future requirements of the country.
- Validation of hydrological and hydrodynamic models including collection of field data and issuing flood forecasts regarding major rivers.
- Flood mapping including collection of required data and information related to major floods.
- Publishing periodic hydrological bulletins, manuals etc.
- Conducting research works and providing consultancy services for other agencies on their request.
Hydrometric Network of Sri Lanka
There are 103 major river basins in Sri Lanka which cover the 90 % of total land extent of the country as shown in Fig. II. The remaining 10% which is situated along the coast and Jaffna peninsula is covered by small watersheds which are not much important in hydrological aspect.