The anatomy of the Yamuna floodplains

General Studies Paper 3

INTRODUCTION

• Battered by heavy rains, the Yamuna looks slow, sluggish and swollen. Last week, the water levels hit a 60-year-high, gushing through elite neighbourhoods built close to the floodplains. Waters advanced towards the Taj Mahal for the first time in half a century.

IMPORTANCE OF YAMUNA

• We talk about rivers in isolation, but floodplains are inseparable from the river channel.
• The river system includes both water and land. Yamuna is a lifeline to five States, and its floodplains are a charging point.
• Yamuna courses east of Delhi, entering the city from Palla village and exiting at the Okhla barrage.
• Farmers near Palla and Hiranki villages traditionally grow rice, wheat, and flowers on the rich silt deposited by the river.
• The floodplains are two km wide on each side. The floodplain along Yamuna’s 22 km run in Delhi, designated as the O zone by the Delhi Development Authority, has an area of approximately 9,700 hectares.
• Zone O supports a large variety of nature-based livelihoods with a low ecological footprint.
• Between Palla and Okhla, the composition of the floodplains changes from farmlands to slums, colonies, flyovers and bridges.
• A river has the “right to expand” and needs to breathe through its flood plains. Any attempt to concretise constricts its air supply.
• As part of river systems, floodplains slow water runoff during floods, recharge groundwater and store excess water, replenishing the city’s water supply.
• When you have sluggish flow, the surplus water stored in the floodplain is released back during the non-monsoon season.
• If you lose the floodplain, you also lose the storage of water.
• Delhi recorded similarly devastating floods in 1978, 1988 and 1995 which inundated floodplains, adversely impacting their health.

DELHI’S MASTER PLAN OUTLINE

• The Yamuna floodplain was designated as a protected area free from construction in the Delhi Masterplan of 1962.
• The Central Ground Water Authority in 2000 also notified the floodplains as ‘protected’ for groundwater management.
• The draft Master Plan For Delhi 2041 divides Delhi into 18 zonal areas, designating Yamuna’s floodplains as ‘Zone O’, delineated in two parts: river zone (active floodplain) and riverfront (regulated construction is allowed).
• The South Asia Network on Dams, Rivers and People (SANDRP) in 2020 found large parts of the Yamuna floodplains and riverbed were “grossly abused” due to lax implementation
• The areas proposed under the Yamuna Riverfront Development (YRDF) plan — which proposes biodiversity parks and ‘recreational’ activities — were within the active floodplain, which could affect the topography, increase pollution and affect flood-carrying capacity.
• The layers of sediments of floodplains create aquifers contributing to the river channel, which in turn rejuvenates the groundwater. But encroachments stop this two-way exchange.
• The river is unable to transport flood waters downstream during monsoons, wet the lands or deposit soil along its banks to preserve the riverine ecosystem.

ROLE OF ENCROACHMENTS

• Floodplains also protect against devastating flash floods by allowing excess water to spread out and storing that surplus.
• However, encroachments restrict the river to a small channel. Any intense rainfall activity swells the river, expanding in height not in width, eventually spilling over with devastating intensity.
• Climate change has intensified rains in frequency and severity, and seen in the Yamuna floods, runoff water comes as a huge gushing flow in a small span of time.
• Floods are inseparable from the hydrological cycle and are required for sediment transport, cleaning the riverbed, rejuvenating the river itself.

WAY FORWARD

• The concept of floodplain zoning is not mainstreamed in the Master Plan and authorities haven’t yet taken cognisance of the river’s right to expand.
• This gap, along with poorly implemented policies, frees up river land for private and public real estate.
• A model draft Bill for defining floodplains and zoning was circulated in 1975. Only four States have drafted a National Floodplains Zoning Policy so far.
• Action can be focused on creating climate-resilient infrastructures, de-silting drains, creating green areas and improving drainage systems.