Basic Features

Basic functions of the Dashboard

• The dashboard provides key hydrological characteristics of 13 river basins of Sri Lanka covered under the CSIAP
• The basins are: Mandakal Aru; Mundeni Aru; Per Aru; Mi Oya; Mee Oya; Kirindi Oya; Karanda Oya; Heda Oya; Yan Oya; Wila Oya; Kala Oya; Kachikumban Aru; Manik Ganga and Malala Oya
• The features include overall land use of the basins; sub-basin wise drainage area; and rainfall range (min., max., and normal)
• It provides the sub-basin wise rainfall-runoff relationship worked out using HEC-HMS model and explains the way to arrive at runoff using the equations
• It also provide a sample worksheet that explains the procedure for estimating the runoff for different values of rainfall for smaller catchments within the basin/sub-basins; and estimate the dependable yield and runoff coefficients
• The models can also be used for basins with similar characteristics in terms of land use and rainfall magnitudes, especially those which are closer

Sr. No	Name of the Basin	LAND USE	TOTAL BASIN AREA in km²	Barren Land	Chena / Other Cultivation	Agriculture	Coconut	Forest	Grassland	Rock	Paddy	Scrub Jungle	Residential	Water	Wetland Forested	Wetland Non-Forested	Open Forest	Marsh Land	Other Types	Sand	Stream area	Tank Area	Abandoned Tank Area	Water Hole Area	Built-up
1	Mi Oya	(km²)	1548.6	2.10	304.20		25.70	229.40	8.50	9.70	253.20	220.90	377.80	111.60	1.60	3.90
		% of the basin area		0.14	19.64		1.66	14.81	0.55	0.63	16.35	14.26	24.40	7.21	0.10	0.25
2	Yan Oya	(km²)	1432.2				0.20	486.80	502.70	8.60	265.30		156.70				5.30	6.60
		% of the basin area					0.01	31.37	32.39	0.55	17.10		10.10				0.34	0.43
3	Mandakal Aru	(km²)	322.1			2.40		206.20			15.30	73.50	3.20					7.00	0.90	4.10	1.40	6.40	1.30	0.40
		% of the basin area				0.70		64.00			4.80	22.80	1.00					2.00	0.30	1.30	0.40	2.00	0.40	0.10
4	Manik Ganga	(km²)	926.73
		% of the basin area				15.00		66.00																	14.00
5	Karanda Oya	(km²)	422
		% of the basin area				25.00		56.00																	7.00
6	Kirindi Oya	(km²)	1134.82
		% of the basin area				27.00		43.00																	14.00
7	Heda Oya	(km²)	613.61
		% of the basin area				39.00		40.00		5.00				2.00						1.00					12.00
8	Wila Oya	(km²)	457.1725
		% of the basin area				25.00		56.00																	7.00
9	Kala Oya	(km²)	2851.04
		% of the basin area		1.00		25.00		56.00		7.00				4.00											7.00
10	Per Aru	(km²)	384.16
		% of the basin area				18.00		67.00																	7.00
11	Mundeni Aru	(km²)	1311.19
		% of the basin area				27.00		54.00																	7.00
12	Kunchikumban Aru	(km²)	256.82
		% of the basin area				16.00		76.00																	1.00
13	Mee Oya	(km²)	111.39
		% of the basin area				37.00		40.00						5.00											17.00
14	Malala Oya	(km²)	427.00
		% of the basin area				29.00		43.00														4.40

The river basin rainfall-runoff models and the related data are the properties of Climate Smart Irrigated Agriculture Project (CSIAP) and the permission is hereby granted for customizing maps, figures and tables and other outputs for academic use. The images must not be altered or reproduced in any manner for profit or otherwise, or used in any manner that misrepresents their original context or purpose. Please ensure that proper credit is given by including the following attribution:

"Data Source: Climate Smart Irrigated Agriculture Project (CSIAP), 2025"