Sustainable Urban Planning

The rise of cities and metropolises have added new dimension to human civilisations. Cities have become the face of modernisation as they cater to public needs in a systematic manner. The people have enhanced access to transportation, communication and other essential infrastructures, which are not available in the rural settings. However, urbanisation has became synonymous with concretisation of surfaces and structures. The fast-paced urbanisation aims to provide facilities to the people at maximum level but this drive sorely misses out the vital environmental aspects that are connected to soil, rivers, greenery and air, among others. The growing concrete infrastructure goes against the law of nature if the ecology is undermined and land use is not heeded sensitively. Failure to address the social and environmental issues invite unintended consequences such as flooding, land subsidence and loss of lives and private and public properties. The ill-planed urban areas suffer floods due to heavy precipitation and river overflows. 

 Climate change induced by the global warming has further exacerbated the matter for it has made rainfall pattern erratic and unpredictable. Last April, deadly floods put Dubai under water.  Similar disasters have hit world's other cities, too. Come rainy season, Nepalis have to reel from floods, landslides and land subsidence. Recently the Kathmandu Valley witnessed sudden flooding that damaged houses built near the river banks. The water levels in the Bagmati River and its tributaries rose, triggering floods that brought debris and wastes into the houses in many places such as Teku, Balkhu, Samakhushi, Dhungedhara, Anamnagar, Bhotebahal, Gyaneshwor and Thamel. Similarly, a big sinkhole opened over inner road in Imadol of Mahalaxmi Municipality-3, Lalitpur and a significant portion of road collapsed in Kamaladi, disrupting the vehicular movements.

Experts claim that the Kathmandu Valley contains huge amount of alluvial soil as it was once a lake. The unplanned urbanisation puts that valley at risk of land subsidence and flooding during the rainy season. The concretisation has disrupted the ground water recharge process. The rainwater cannot make its way into the ground and passes into the rivers via the water channels, causing floods in the residential areas. The encroachment on the riversides, rapid urbanisation, defective drainage systems and unplanned settlements are responsible for the flooding and formation of sinkholes. The collapse of the road over the Tukucha Khola at Kamaladi occurred due to underground soil erosion when there is huge water flow.  The dilapidated condition of the culvert is also attributed for the land subsidence at the Kamaladi.

The falling of a section of Kamaladi road has sent shocks across the residents, whose houses are built on the Tukucha. There is high chance of the soil erosion when the culverts built over the very rivulet crumble during the heavy downpours. The concerned authorities must swing into action to avert the possible loss of lives and properties. A study has revealed that river corridor of Dhobi Khola, particularly in Dhumbarahi, Gyaneswor and Anamnagar, is more vulnerable to floods due to low river depth. The cities in the Valley lack proper groundwater recharge systems, which is the cause of inundation and land subsidence. Water resources have been overexploited to meet the demand of the rising population. Now planners must focus on appropriate design of sewer and drainage systems to boost discharge capacity of land. Moreover, the ancient Valley has absorbed the population more than its capacity. The urbanisation policy should prioritise the planned settlement in a way that protects water resources and rivers.