The frequent urban flooding in many states highlights the issues regarding management of urban water bodies in Indian. Examine. Also discuss how Urban watersheds are affected by anthropogenic activities.
Urban flooding is the accumulation of floodwaters that result when the inflow of storm water exceeds the capacity of a drainage system to infiltrate water into the soil or to carry it away.
There has been an increasing trend of urban flood disasters in India over the past several years whereby major cities in India have been severely affected. A special feature in India is that we have heavy rainfall during monsoons. There are other weather systems also that bring in a lot of rain. Storm surges can also affect coastal cities/ towns. Sudden release or failure to release water from dams can also have severe impact. In addition, the urban heat island effect has resulted in an increase in rainfall over urban areas. Global climate change is resulting in changed weather patterns and increased episodes of high intensity rainfall events occurring in shorter periods of time. Then the threat of sea-level rise is also looming large, threatening all the coastal cities. Cities/towns located on the coast, on river banks, upstream/ downstream of dams, inland cities and in hilly areas can all be affected.
Issues with urban flooding
- It causes damage to infrastructure, roads and settlements, industrial production, basic supplies, post disaster rehabilitation difficulties etc.
- Contamination of water results in trauma, loss of life, injuries and disease outbreak, r etc.
- Loss of habitat, tree and forest cover, biodiversity loss and large scale greenery recovery failure is an environmental threat.
- Increased traffic congestion, disruption in rail services, disruption in communication- on telephone, internet cables causing massive public inconvenience is another concern.
Anthropogenic activities that affect urban watersheds
- Waste water from a tributary drain, sewage draining, industrial effluents, urban storm water runoff, solid waste and debris, pollution from agricultural fertilizers and chemicals etc. reduces water carrying capacity.
- Through land reclamation to accommodate growing urban population can lead to loss of whole or certain portions of water bodies.
- riverbank stabilization has been reducing because of developmental activities on flood plains
- increase in urban population without increase in infrastructure for disposal of waste is one of the effect for urban flooding
- illegal mining activities is a major concern
- The type and amount of vegetation, and the plant community structure, can greatly affect the storage capacity in any watershed.
- simple, overburdened drainage, frenzied and unregulated construction, buildings constructed without paying any heed to the natural topography and hydro-geomorphology all adds to the damage.
The need of the hour is urgent rebuilding of cities such that they have the sponginess to absorb and release water without causing so much misery and so much damage to the most vulnerable of our citizens, as we have seen.