Surreal illustration of Western Ghats showing contrasting rainfall impacts.

Monsoon Mayhem: How Rainfall Changes Are Rewriting India's Water Story

Samir D’Costa in Climate & Environment June 2025 • 4 min read.

"Unpacking the shifting rainfall patterns in Southern Western Ghats and their surprising impact on rivers and groundwater."

The Western Ghats, a mountain range running along the western coast of India, is the lifeline for the entire peninsular region. Like a natural water tower, it captures monsoon rains that feed the rivers, which sustains agriculture and life for millions. But what happens when the rain itself starts to change?

For decades, scientists have studied the overall weather patterns in major river basins. However, less attention has been paid to how rainfall affects the smaller, more natural river systems found on either side of the Western Ghats. These unique ecosystems are biodiversity hotspots, making understanding their water systems crucial.

A new study has examined how rainfall patterns have shifted in recent decades and how those shifts are affecting the water flow of key rivers in the southern Western Ghats. This research reveals some surprising trends that could have major implications for water management and conservation.

The Rain Is Changing: A Tale of Two Monsoons

Surreal illustration of Western Ghats showing contrasting rainfall impacts.

The study looked at rainfall data over the last three decades, analyzing annual and seasonal trends. The findings revealed a concerning pattern: a decrease in rainfall during the southwest monsoon season (the period of heaviest rainfall) coupled with an increase in rainfall during the northeast monsoon.

Think of it like this: traditionally, the southwest monsoon has been the reliable workhorse, providing the bulk of the year's water. Now, it's weakening, while the northeast monsoon, usually a smaller contributor, is gaining strength. This shift has a direct impact on the rivers that depend on these rains.

Here's a quick breakdown of what the research uncovered:

Decreasing rainfall in the southwest monsoon.
Increasing rainfall in the northeast monsoon.
Declining water flow in rivers that depend on the southwest monsoon.
Changes in how efficiently rainfall translates into river flow.

Rivers flowing west from the Ghats, which depend heavily on the southwest monsoon, are experiencing reduced water flow during that critical season. The amount of rainfall that actually ends up in the rivers (known as the runoff coefficient) is also changing, indicating alterations in how the land absorbs and releases water.

What Does This Mean for the Future?

This study highlights a critical need for better water management strategies that take these changing rainfall patterns into account. Traditional approaches may no longer be sufficient. The research suggests a shift towards more localized water conservation methods. Techniques like rainwater harvesting and the construction of small farm ponds can help capture and store water during periods of intense rainfall, allowing it to slowly replenish groundwater reserves and sustain river flow during drier periods. Ultimately, adapting to these changes is crucial for ensuring the long-term water security and ecological health of the Western Ghats region.

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This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1007/s12594-018-1065-9, Alternate LINK

Title: Impact Of Rainfall Variability On River Hydrology: A Case Study Of Southern Western Ghats, India

Subject: Geology

Journal: Journal of the Geological Society of India

Publisher: Springer Science and Business Media LLC

Authors: K. Sreelash, Rajat Kumar Sharma, J. A. Gayathri, B. Upendra, K. Maya, D. Padmalal

Published: 2018-11-01

Everything You Need To Know

What specific changes in rainfall patterns are being observed in the Southern Western Ghats?

The research indicates a concerning trend of decreasing rainfall during the southwest monsoon season, traditionally the period of heaviest rainfall, and an increasing rainfall during the northeast monsoon. This shift disrupts the traditional water supply pattern, impacting the rivers that heavily rely on the southwest monsoon for their water flow.

What data and regions were analyzed to determine the effect on the rivers in the Southern Western Ghats?

The study examined rainfall data over the last three decades in the Southern Western Ghats, analyzing annual and seasonal trends. It focused on how these rainfall pattern shifts affect the water flow of key rivers, especially those dependent on the southwest monsoon. Also the amount of rainfall that ends up in the rivers was studied.

How is the reduced rainfall during the southwest monsoon specifically impacting rivers in the Southern Western Ghats?

Rivers flowing west from the Ghats, heavily dependent on the southwest monsoon, are facing reduced water flow during that critical season. Furthermore, alterations in the runoff coefficient indicate changes in how the land absorbs and releases water, affecting the efficiency of rainfall translation into river flow.

What solutions does the study suggest to manage the changing rainfall patterns in the Southern Western Ghats?

The study underscores the urgent need for localized water conservation methods such as rainwater harvesting and small farm ponds. These techniques can capture and store water during intense rainfall periods, slowly replenishing groundwater reserves and sustaining river flow during drier periods. This approach acknowledges the weakening southwest monsoon and leverages the increasing northeast monsoon.

What are the broader implications of the changing monsoon patterns and water flow for the Southern Western Ghats region?

Changes in monsoon patterns and water flow in the Southern Western Ghats could significantly impact agriculture, biodiversity, and overall water security for millions who depend on these water resources. A decline in the southwest monsoon could lead to water scarcity, affecting crop yields and livelihoods. Shifts in river flow could disrupt ecosystems, impacting biodiversity hotspots. Without adapting water management strategies, the long-term ecological health and water availability of the region is at risk. Addressing these changes proactively is essential for mitigating these far-reaching impacts.