Mangaluru: The southwest monsoon has taken an unusual turn in Dakshina Kannada this year, with the district witnessing frequent but short-lived spells of heavy rain instead of the prolonged downpours traditionally associated with the coastal region. According to the India Meteorological Department (IMD), the changing rainfall pattern has contributed to a significant rainfall deficit and could adversely affect groundwater recharge despite rain occurring on most days.

The IMD has reported that Dakshina Kannada recorded a 33 per cent rainfall deficit in June and has forecast below-normal rainfall for the remainder of the southwest monsoon season. Coastal Karnataka is expected to receive 30 to 40 per cent less rainfall than normal during August and September, largely due to the influence of El Niño.

June records 33 per cent rainfall deficit

According to IMD data, rainfall across Dakshina Kannada has remained well below seasonal averages despite regular showers.

The department noted that the district experienced a 33 per cent rainfall deficit in June, while forecasts indicate that rainfall is likely to remain below normal over the coming months.

The weather agency has projected a 30 to 40 per cent rainfall deficit across coastal Karnataka during August and September, attributing the outlook mainly to the prevailing El Niño conditions, which are known to weaken monsoon activity over parts of India.

Rainfall pattern undergoes significant change

Sajeev R., Scientist-E at the IMD’s Doppler Weather Radar Centre in Mangaluru, said the district is expected to receive around 1,035 mm of rainfall during July, spread over approximately 28 rainy days.

However, he observed that the nature of rainfall has changed considerably compared to previous years.

“Rain is occurring on most days, but it is no longer the continuous downpour that the coast is known for. Instead, we are seeing brief but intense showers that last for 15 to 20 minutes before stopping,” he said.

The shorter, high-intensity rainfall events differ from the prolonged moderate rainfall that traditionally characterised the southwest monsoon in the coastal belt.

Groundwater recharge likely to decline

IMD officials have expressed concern that the altered rainfall pattern may reduce groundwater recharge across the district.

According to Sajeev, heavy rain falling over a short period generates greater surface runoff, allowing less water to seep into the ground.

“When rain falls in short, heavy spells, much of the water runs off quickly. To improve groundwater levels, we need to reduce runoff and increase the amount of water that percolates into the soil,” he explained.

Experts believe sustained rainfall over longer durations is generally more effective in replenishing groundwater aquifers than brief, intense downpours.

Weaker monsoon circulation observed

The IMD has also observed that the southwest monsoon circulation has been comparatively weaker this season.

Although monsoon winds continue to flow along the Karnataka coast, they have lacked the strength and persistence normally associated with an active monsoon, resulting in lower overall rainfall.

The weakened circulation has contributed to reduced rainfall activity across Dakshina Kannada despite the regular occurrence of rain-bearing clouds.

Highly localised showers becoming common

Another feature of this year’s monsoon has been the increasing localisation of rainfall.

According to IMD, convective cloud formation has resulted in sharp variations in rainfall over short distances.

Sajeev explained that one locality may receive around 5 cm of rain while another area just a few kilometres away records only 2 cm during the same weather event.

He noted that such uneven rainfall distribution has become increasingly common this monsoon season, making local weather conditions less predictable than in previous years.

Some positive impacts despite rainfall deficit

While the rainfall deficit has raised concerns about water resources, the altered monsoon pattern has also brought certain advantages.

According to the IMD, the absence of prolonged daytime rainfall has allowed normal daily life and economic activities to continue with fewer disruptions.

Schools are expected to experience fewer rain-related holidays, while the reduced duration of heavy rainfall may also lower the frequency of flood situations compared to previous monsoon seasons.

The department further noted that sea conditions have remained comparatively calmer than during recent southwest monsoons, providing some relief to coastal communities and marine activities.

Need for water conservation

The changing monsoon pattern highlights the growing importance of effective water conservation and groundwater recharge measures in Dakshina Kannada.

With rainfall increasingly occurring in short, intense bursts rather than continuous spells, experts believe efforts to harvest rainwater, reduce surface runoff and improve groundwater infiltration will become even more critical in maintaining long-term water security.

As the monsoon progresses, the IMD will continue monitoring rainfall trends and weather patterns across coastal Karnataka, while authorities remain watchful of the evolving impact of El Niño on the region’s seasonal rainfall.