A New Solution for City Water:Quality Drinking Water from the River Floodplains

Abstract

MANY parts of the world and India are poised for water jeopardy. For example, most parts of northwestern and peninsular India, northern China and California, USA are water-stressed 1,2 . In many parts of India groundwater levels are down by about 20 m and rivers are overused and silted and cannot be exploited further. Silt and sewage-infested riverbeds can be the cause of natural catastrophes -a recent ones being the flood in Kashmir and Chennai.Cities need to find a solution for sourcing water that is not injurious to the planet. For example, a dam is hugely invasive for the mountain ecology and the rivers, and needs a large-scale resettlement of the people. Tertiary recycling of wastewater, good for just kitchen use and not drinking, is expensive. In a city, there is no space for large reservoirs, which would anyway lose about 2 m of water every year by evaporation 3 . It is crucial to find a new source of water and use it non-invasively as a perennial resource.The floodplains of the Himalayan river systems are extensive sandy aquifers that are 5-20 km wide and on an average about 100 m deep, and run for hundreds or even thousands of kilometres along the rivers 4 . The floodplains are a huge natural storage of quality water without any evaporation losses.India receives 80% of its rainfall in about three months during monsoon 5 . This recharges the floodplains of the rivers on an annual basis. Here we show that for a large number of cities by the rivers, an ecologically safe use of such rainfall recharge can provide a non-invasive solution for city water.To be sustainable and perennial, it is crucial that we do not use any more water than is naturally recharged. In this study we examine in detail, the hydrology of floodplain aquifers of River Yamuna and work out the quantum of natural recharge in the northern part of its floodplain in Delhi. From this we work out an ecological process for a local, perennial and sustainable supply of quality water for Delhi, and other towns and cities located near the floodplains of a river.Till now the floodplains have been used randomly without any detailed research and study. Often this has resulted in indiscriminate use, terminally polluting such aquifers. Hence, in this study we work out an ecologically safe process for sustainable water use from these aquifers.

Recent Scientific Perspectives on the Indian Hydrogeology

“…The relatively low stream power of River Yamuna having direct effect on the River morphology of the middle stretch has also been attributed to the excessive groundwater withdrawal along these reaches and the catchment (Bawa et al 2014). It has been established that the efficient conjunctive use of surface and groundwater in the overexploited aquifers can prevent seasonal drying up of the non-glacier linked Rivers (Shekhar et al 2018). River bank infiltration can be used effectively for water supply for the urban areas located on suitable aquifer system on the bank of river.…”

“…The sea water intrusion in the coastal aquifers has been studied through a 3 dimensional variable density conceptual phreatic model. Rao et al (2018)…”

“…The water quality of River Garra at Shahjahanpur, Uttar Pradesh was studied by Khan et al (2016a). The Groundwater quality issue in arid and semi-arid region of Rajasthan state and their vulnerability has been assessed and possible remedial measures were also discussed Ahadaand Suthar (2017); Chaudhary and Sathees Kumar (2018) and Gupta and Sharma (2018).The water quality index based assessment of groundwater quality for Varanasi was accomplished by Chaurasia et al (2018) and the nitrate contamination in the groundwater of Varanasi was assessed by Ahamad et al (2018). Similarly, the anthropogenic influence on the groundwater quality of the shallow aquifers was studied by Saba et al (2018).…”