Kalu Ganga ( si, කළු ගඟ; literally: Black River) is a

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of ...

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

. Measuring in length, the river originates from Sri Padhaya and reach the sea at

Kalutara Kalutara ( si, කළුතර, ta, களுத்துறை) or Kalutota is a major city in Kalutara District, Western Province, Sri Lanka. It is also the administrative capital of Kalutara District. It is located approximately south o ...

. The Black River flows through the

Ratnapura Ratnapura (; ) ("City of Gems" in Sinhala and Tamil) is a major city in Sri Lanka. It is the capital city of Sabaragamuwa Province, as well as the Ratnapura District, and is a traditional centre for the Sri Lankan gem trade. It is located o ...

and the

Kalutara District Kalutara District ( si, කළුතර දිස්ත්‍රික්කය; ta, களுத்துறை மாவட்டம் ''Kaḷuttuṟai Māvaṭṭam'') is one of the 25 districts of Sri Lanka, the second level administrative d ...

and pass the city

. The mountainous forests in the Central Province and the

Sinharaja Forest Reserve Sinharaja Forest Reserve is a forest reserve and a biodiversity hotspot in Sri Lanka. It is of international significance and has been designated a Biosphere Reserve and World Heritage Site by UNESCO. According to International Union for Conse ...

are the main sources of water for the river. The

Edwardian The Edwardian era or Edwardian period of British history spanned the reign of King Edward VII, 1901 to 1910 and is sometimes extended to the start of the First World War. The death of Queen Victoria in January 1901 marked the end of the Victori ...

manor,

Richmond Castle Richmond Castle in Richmond, North Yorkshire, England, stands in a commanding position above the River Swale, close to the centre of the town of Richmond. It was originally called Riche Mount, 'the strong hill'. The castle was constructed by Ala ...

is on the banks of the river near

. 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 the socio-economic profile greatly. During the past several years, many researchers have investigated climatic changes in the main river basins of the country, but no studies have been done on climatic changes in the Kalu Ganga basin. Therefore, the objective of this study was to investigate precipitation trends in the 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. On average, a -0.98 trend with an annual rainfall reduction of 12.03 mm/year was found. April and August were observed to have strongly decreasing trends. July and November displayed strong increasing trends. In conclusion, 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

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 at 4000 mm and leads to 4000 million m³ of annual flow. The Kalu Ganga originates from the central hills of the 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 the upper part and mild gradients in the 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 is a potential area for rice production. During the past several years, attention has been paid to the study of precipitation changes in the main river basins of Sri Lanka. El Niño-southern oscillation influences on stream flow in Kelani River. In studied 2005 hydrology and environmental flows in the Walawe River basin. However, we could not find any academic literature regarding climatic changes in the Kalu Ganga basin, which is one of the four main rivers in Sri Lanka. The major possible

effects of climate change The effects of climate change impact the physical environment, ecosystems and human societies. The environmental effects of climate change are broad and far-reaching. They affect the water cycle, oceans, sea and land ice ( glaciers), sea le ...

may include variability in water resources, increase

desertification Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid. It is the spread of arid areas caused ...

loss of biodiversity Biodiversity loss includes the worldwide extinction of different species, as well as the local reduction or loss of species in a certain habitat, resulting in a loss of biological diversity. The latter phenomenon can be temporary or permanent, de ...

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 the general circulation model reveal that increased global temperature could lead to an increase in the amount and intensity of regional precipitation. Precipitation is a good indication of the impacts of climate change on water resources. Changes in precipitation patterns are very important for water resources managers to deal with water resources planning and management. Variations in precipitation over daily, seasonal, annual, and decadal timescales influence water 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 climate change in the Kalu Ganga basin.

References

Rivers of Sri Lanka Bodies of water of Kalutara District {{SriLanka-river-stub

Introduction

See also

References