Urbanisation hits ground water in Vizag despite normal rainfall

Visakhapatnam: Groundwater depletion is generally associated with years of deficient rainfall and excessive groundwater extraction, often aggravated by climatic events such as El Nino.

However, a recent analysis by the Central Ground Water Board (CGWB) found that groundwater levels in the urban areas of Visakhapatnam and Anakapalle continued to decline despite largely stable annual rainfall, indicating that rapid urbanisation has emerged as a major driver of depletion.Between 2013 and 2023, groundwater levels declined by up to 0.77 metres (m) a year during the pre-monsoon period and 1.23 m a year during the post-monsoon period.

In densely built-up localities such as Seethammadhara and Maharani Peta, the water table has fallen to more than 20 m below ground level.The pattern is particularly concerning because monsoon rainfall normally replenishes aquifers and raises groundwater levels after the rainy season. The steeper post-monsoon decline suggests that aquifers are no longer able to effectively capture seasonal rainfall, indicating a breakdown in the natural recharge mechanism and year-round depletion of groundwater reserves.

The CGWB analysis attributes this trend largely to rapid urbanisation. Built-up areas more than doubled from 119 sq. km to 283 sq. km between 2013 and 2023. The 137 percent increase in built-up area over the decade replaced vast stretches of naturally permeable land with impermeable surfaces such as concrete, asphalt and dense infrastructure, significantly reducing groundwater recharge.These findings are part of the recently prepared ‘aquifer management plan of Visakhapatnam and Anakapalli urban agglomerations’, prepared by the Central Ground Water Board (CGWB).

The study was carried out under the National Aquifer Mapping and Management Programme (NAQUIM) 2.0. The team of officials comprised Lakshmi Narayana Damodara, Md Sarif Khan, Nilima Patra, T. Venkata Giri, S.K. Ratha, Ravi Kumar Gumma and G.

Krishnamurthy from the CGWB offices in Hyderabad and Visakhapatnam.The surge in urbanisation can be understood from the rapid pace of construction across the Visakhapatnam-Anakapalli urban corridor.

Large-scale residential layouts, apartment complexes, industries, educational institutions and commercial establishments have transformed areas such as Yelamanchili, Parawada, Anakapalli, Kurmannapalem, Madhurawada, Anandapuram, Tagarapuvalasa, Pendurthi and Simhachalam over the past decade.

This sustained real estate and infrastructure boom has dramatically altered land use, leaving fewer open spaces for rainwater to percolate into the ground.For instance, between 2013 and 2023, cropland shrank from 221 sq. km to 123 sq. km, plantation and hilly areas declined from 269 sq. km to 254 sq. km, and barren or open land decreased from 115 sq. km to 71 sq. km. As permeable land has steadily disappeared, rainwater that would normally seep into the soil is now converted into surface runoff. Instead of recharging aquifers, it flows over concrete surfaces into stormwater drains before eventually reaching the sea or other surface water bodies.The study also highlights a deterioration in groundwater quality due to rapid urbanisation and industrial activity. The average electrical conductivity of groundwater is about 1,232 µS/cm. Still, it exceeds 3,000 µS/cm in industrial areas such as Pedagantyada and Parawada, indicating a high concentration of dissolved salts, likely from industrial effluents. Nitrate concentrations range from 1 to 305 mg/L, with nearly 35 percent of groundwater samples exceeding the safe limit of 45 mg/L, largely due to inadequate sewerage infrastructure that allows domestic wastewater to seep into shallow aquifers.Fluoride levels are generally within the permissible limit of 1.5 mg/L, although a few locations recorded higher concentrations, which the study attributes to natural geological conditions rather than pollution.