A new scheme for large-scale natural water storage in the floodplains: the Delhi Yamuna floodplains as a case study.

The top layer of accumulated sand washed down by floods over millions of years, makes river floodplains into giant aquifers. We propose a scheme for the natural storage of excess monsoon river-water discharge in the extensive and deep sand top layer of the floodplain of the river. The excess monsoon discharge can be used for a regulated inundation of an embanked area of the floodplain - to soak in and store the water. This storage can then be used for the withdrawal of water during the dry months. We illustrate this by an evaluation of the potential of the Yamuna floodplains in the National Capital Territory of Delhi and show that there can be an annual yield of 600-900 MCM of water, which is three-fourths the total water supply to Delhi. This makes it an invaluable natural resource potentially worth about Rs 6000-9000 crores a year of non-invasive use.