Rapid urbanisation and climate change are intensifying urban flooding across cities worldwide. In India, increasingly intense rainfall events, expanding impervious surfaces that prevent rainwater from soaking into the ground, and declining groundwater recharge have made waterlogging a recurring urban challenge.
Surat, one of India’s fastest-growing cities, is home to over 8.2 million people (estimated population as of 2024, SMC). Located in Gujarat, on the banks of the Tapi River, the city receives about 1200 mm of rainfall every year from the southwest monsoon. Despite the city’s extensive network of stormwater drains and creeks, it experiences waterlogging and flood-like situations during high-intensity rainfall.
Surat Municipal Corporation (SMC) has taken several initiatives to overcome flooding and strengthen urban water resilience in the city.
- Creeks are regularly desilted, maintained, and improved to enhance stormwater conveyance and minimise flood risks.
- Comprehensive stormwater and drainage network maintenance is in place to minimise waterlogging and improve drainage capacity.
- Rainfall, river and creek water levels are monitored in real time, and early warning mechanisms have been established to improve disaster preparedness. The Integrated Command and Control Centre integrates real-time data from multiple departments, enabling timely decision-making, coordinated emergency response, and efficient management of flood and waterlogging situations.
- The Corporation also promotes rooftop rainwater harvesting systems in public buildings, residential developments, and commercial establishments to encourage groundwater recharge.
A newer initiative addresses a previously unexplored dimension of urban water management by focusing on subsurface investigations or gathering data about the soil, rock, groundwater, and underground structures.
Understanding the Underground
Recognising that conventional drainage solutions alone cannot address urban waterlogging, SMC adopted a data-driven approach. The Corporation initiated hydrogeological and geophysical investigations at identified waterlogging hotspots to understand groundwater recharge potential, estimate aquifer depths, and identify zones with recharge potential. The findings guided the implementation of vertical groundwater recharge to channel excess water into the subsurface (aquifers) where horizontal infiltration is limited due to dense urban development and limited open spaces.
Pilot Case: Low-lying areas of Saniya Hemad in the East Zone area of Surat
The primary cause of waterlogging at this low-lying site is its proximity to the Mithi Creek. The creek’s higher elevation than the surrounding area creates backflow conditions that prevent stormwater from draining efficiently. This caused waterlogging up to 8-10 ft for 12-24 hours.
SMC studied Digital Elevation Models (DEMs) and GIS-based contour maps to identify locations with low elevation surrounded by creeks for performing electrical resistivity tests. These tests indicate the deep soil strata of different categories and available aquifers with the capacity to hold more water.
Resistivity survey analysis using the passive electromagnetic (EM) exploration method that measures orthogonal components of electric and magnetic fields on Earth’s surface identified large-capacity aquifer zones at depth of approximately 45–60 m.
An important consideration during site selection was that the aquifer in the recharge zone was not internally connected with creeks. If any direct connection existed between the aquifer in the recharge zone and the creek, the recharged water would eventually flow back to the creek, reducing the effectiveness of the intervention.
The collected data from the resistivity survey were processed to generate vertical resistivity profiles and subsurface layer interpretations.
Results of the Exercise
Groundwater was encountered at a depth of approximately 17–22 m below ground level, while the pumping water level was in the range of 36–42 m, indicating the presence of a good underground water-bearing layer. Based on the investigation, the site was found suitable for the development of a recharge well. A recharge bore extending up to approximately 46 m depth was recommended to facilitate the direct recharge of stormwater into the identified aquifer, thereby reducing waterlogging and enhancing groundwater replenishment.
How does this benefit the people of Surat?
The intervention is expected to reduce the extent and duration of waterlogging at the project locations by facilitating rapid infiltration of accumulated stormwater into the identified aquifer zone. This will allow the captured rainwater to contribute to groundwater replenishment rather than flowing back into adjacent creeks. Before recharge, the collected stormwater is proposed to undergo appropriate pretreatment and screening to minimise the entry of sediments and contaminants into the aquifer.
For the residents of Surat, this means resuming daily activities more quickly due to reduced waterlogging, even after intense rainfall. It will also reduce disruption to homes, local businesses, roads and access to essential services. It can also help reduce prolonged inundation and, over time, minimise recurring damage and maintenance requirements for local roads and public infrastructure.
Based on the potential of the pilot investigation, the city is exploring the replication of this approach at other locations prone to waterlogging. The city also envisions mapping aquifers across the city to identify recharge zones and support evidence-based groundwater management. This data-driven approach can guide urban water management planning in Surat, enhancing the city’s water security and strengthening its climate resilience.
The author, Shri M. Nagarajan, is a 2009-batch IAS officer of the Gujarat Cadre. He is a technocrat and known widely for innovative use of technology in governance. He is currently serving as State Project Director, Samagra Shiksha Gujarat, Gandhinagar. He has previously served as the Municipal Commissioner of Surat.