Kalu Ganga

Kalu Ganga (Sinhala: කළු ගඟ; literally: Black River) is a river in Sri Lanka. Measuring 129 km (80 mi) in length, the river originates from Sri Padhaya and reach the sea at Kalutara. The Black River flows through the Ratnapura and the Kalutara District and pass the city Ratnapura. The mountainous forests in the Central Province and the Sinharaja Forest Reserve are the main sources of water for the river.[1]

Kalu Ganga
Kalu Ganga in Ratnapura
Kalu Ganga (Sri Lanka)
Native nameකළු ගඟ (Kalu Ganga)
Location
CountrySri Lanka
Physical characteristics
SourceSri Padaya
 • elevation2,400 m (7,874 ft)
MouthIndian Ocean
 • location
Kalutara
 • elevation
1m
Length129 km (80 mi)
Basin size2,766 km2 (1,068 sq mi)
Basin features
Tributaries 
 • leftKukule River

Kalu Ganga basin is one of the most important river basins in Sri Lanka which receives very high  rainfalls  and  has  higher  discharges.  Due  to  its  hydrological  and  topographical characteristics,  the  lower  flood  plain  suffers  from  frequent  floods  and  it  affects  socio-economic profile greatly. During the past several years, many researchers have investigated climatic  changes  of  main  river  basins  of  the  country,  but  no  studies  have  been  done  on climatic  changes  in  Kalu  Ganga  basin.  Therefore,  the  objective  of  this  study  was  to investigate  precipitation  trends  in  Kalu  Ganga  basin.  Annual  and  monthly  precipitation trends  were  detected  with  Mann-Kendall  statistical  test.  Negative  trends  of  annual precipitation were found in all the analyzed rainfall gauging stations. As an average, -0.98 trend with the annual rainfall reduction of 12.03 mm/year was found. April and August were observed to have strong decreasing trends. July and November displayed strong increasing trends.  In  conclusion,  whole  the  Kalu  Ganga  basin  has  a  decreasing  trend  of  annual precipitation and it is clear that slight climatic changes may have affected the magnitude and timing of the precipitation within the study area

Introduction
Downstream view, in Ratnapura.

Kalu  Ganga  basin  is  the  second  largest river basin in Sri Lanka covering 2766 km2 and  much  of  the  catchment  is  located  in the  highest  rainfall  area  of  the  country, which reflects the high annual rainfall. The annual rainfall in the basin is averaged to 4000mm and leads to 4000 million m3 of annual  flow.The  Kalu  Ganga  originates from  the  central  hills  of  wet  zone  at  an altitude of 2250 m and garners rainfall on the western slopes and falls out to the sea at Kalutara after traversing about 129 km. The basin has steep gradients in upper part and  mild  gradients  in  lower part.  Due  to these  hydrological  and  topographical characteristics of the river basin, its lower flood  plain  suffers  from  frequent  floods during  the  Southwest  monsoon  season. Therefore,  the  damages  to  the  socio-economic  profile  are  significantly  high since the lower flood plain of Kalu Ganga is densely  populated  and  it is  a  potential area  for  rice  production.  During the  past several  years,  attention  has  been  paid  to study  on  precipitation  changes  of  main river basins of Sri Lanka. El Niño-southern oscillation influences on stream  flow  in  Kelani  River.[2] In studied 2005  hydrology and environmental flows in the Walawe  River  basin.  However,  we couldn’t  find  any  academic  literature regarding climatic changes in Kalu Ganga basin, which is one of the four main rivers in Sri Lanka. The major possible effects of climate change may include variability in water  resources,  increase  desertification, loss  of  biodiversity  and  changes  in agricultural  productivity. One of the most significant consequences  resulting  from  climate change  may  be  the  alteration  of  regional hydrological  cycles  and  subsequent changes in stream flow regimes. Studies of general  circulation  model  (GCM)  reveals that  increased  global  temperature  could lead to increase the amount and intensity of regional precipitation. Precipitation is a good  indication  of  the  impacts  from climate  change  on  water  resources. Changes in precipitation patterns are very important for water resources managers to deal with the water resources planning and management.  Variations  in  precipitation over  daily,  seasonal,  annual,  and  decadal timescales  influencewater  resource systems.  In  addition  to  the  studies  on short-term  variability  of  precipitation, long-term  detection  of  precipitation  is essential  for  understanding  the  potential impacts on water resources resulting from climate change. Therefore, the objective of this  study  was  to  investigate  long-term precipitation  trends,  which  is  one  of  the crucial  parameters  in  climatic  change,  in Kalu Ganga basin.[3]

gollark: Apiologically gradientous.
gollark: The jabuapiolic algorithm?
gollark: There are probably out of band signals too anyway.
gollark: I see.
gollark: Does that work for you?

See also
  • List of rivers in Sri Lanka

References
  1. Development of a Flood Forecasting Model For Kalu River and Kelani River Basins in Sri Lanka using Radial Basis Function Neural Networks
  2. Lareef, Z. (2003). Sensitivity of Kelani streamflow in Sri Lnaka. Sri Lanka.
  3. Dharmasena, G.T. (2006). Integrated water resources management and sound information system-Sri Lankan experience. Sri Lanka.


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