When a City Loses Its Natural Drainage

Documented facts

• Land-use research documents substantial conversion of Guwahati's hillslopes and wetlands to built-up area since 2001 (published urban land-use studies).

  Documented evidence

• Deepor Beel, designated a Ramsar wetland in 2002, lies within Guwahati's hydrological setting and receives urban runoff (Ramsar information sheet).

  Documented evidence

• Assam State Disaster Management Authority reports urban flooding in Guwahati during most monsoon seasons (ASDMA situation reports).

  Documented evidence

Timeline

1. January 1, 1986
   Environment (Protection) Act establishes the umbrella environmental framework.
   Documented evidence
2. June 19, 2002
   Deepor Beel designated a Ramsar site.
   Documented evidence
3. September 26, 2017
   Wetlands (Conservation and Management) Rules notified.
   Documented evidence

Geographical context

Guwahati occupies a bowl between the Shillong plateau's foothills and the Brahmaputra. Water arriving from the hills west of the city historically drained into Deepor Beel, a wetland on the city's edge that is also a Ramsar site of international importance. The wetland still receives urban water, but its margin has been built upon and its bed raised by silt. Low-lying wards along the wetland and near the river flood repeatedly, while the hillsides that generate the runoff are themselves being cut for construction.

Scientific context

Urban flooding here is a runoff problem before it is a rainfall problem. Vegetated slopes slow water and allow it to infiltrate; cut slopes and paved surfaces shed it almost immediately and carry soil with it. Silt reduces the storage volume of drains and wetlands at the same time as peak flows increase. Deepor Beel's ecological character — the combination of processes and services for which it was listed under Ramsar in 2002 — is directly affected by that siltation and by encroachment at the margins.

Applicable environmental law

• · Environment (Protection) Act 1986 and EIA Notification 2006
• · Wetlands (Conservation and Management) Rules 2017
• · Disaster Management Act 2005

Community response

Fishers and farmers around the wetland have documented changes in water depth and fish catch across decades, knowledge that rarely enters drainage planning. Resident groups in flood-prone wards have petitioned planning authorities and the National Green Tribunal over construction on hillslopes and at the wetland boundary. Local responses have focused on two demands: enforcement of existing protections, and drainage maintenance that treats the wetland as infrastructure rather than as vacant land.

Institutional response

Responsibility is divided. The development authority holds planning powers, public works agencies build and maintain drains, and the state pollution and forest authorities hold environmental mandates; the tribunal has jurisdiction where those mandates are not applied. The recurring institutional problem is coordination: a building permission on a hillslope changes runoff for a drainage network managed by another agency, and neither is required to assess the combined effect.

Current documented status

Flash flooding continues in low-lying wards during intense monsoon showers. Deepor Beel retains its Ramsar listing while pressures at its margins persist, and drainage works proceed ward by ward rather than as a catchment plan.