Rainwater Harvesting: The Key to Mitigating Flooding and Protecting Soil Health

In our previous blog, we delved into the swift cascading of water from upstream regions, unfortunately resulting in a rapid departure without replenishing groundwater aquifers.

Consequently, this water accumulates downstream, particularly in plains and farmlands, for an extended and undesirable duration. Besides the visible surface flow, there is an ongoing, invisible subsurface movement beneath the Earth’s surface.

When water falls on hills, it can infiltrate the ground, becoming subsurface water. Excess water accumulates in the subsurface if the soil is saturated or the terrain is poorly drained. It then flows downhill, potentially causing flooding through a process called emergence.

This type of flooding disrupts the delicate ecological balance in a given area, affecting the intricate relationship between soil and plants. Plants require a specific depth of aerated soil for optimal growth, with oxygen playing a vital role.

The Impact of Flooding on Soil

The aftermath of such flooding leads to waterlogged soil, nearing saturation and impeding aeration, creating anaerobic conditions. This depletion of oxygen in the root zone adversely impacts microorganisms crucial for supporting plant growth, restricting overall plant growth.

Water logging reduces soil temperature and increases dampness, disrupting biological activities within the soil. It also vastly affects operations related to soil enrichment and development, affecting irrigated agricultural lands.

Water logging often coincides with soil salinity, impeding the leaching of salts brought in by irrigation water. This exacerbates adverse effects, especially when salts from lower soil layers are transported upward by capillary action.

Rise in soil salinity disrupts nutrient absorption by plant roots, damaging plantations and altering the physical characteristics of the soil. The soil becomes less permeable to water and more prone to runoff, negatively impacting neighboring lands and vegetation. Even fodder grown in such soil may pose health risks to livestock.

Based on our three decades of experience, we have learned that flooding exerts a prolonged detrimental influence on soil. While immediate effects may not be readily apparent, long-term consequences involve a gradual degradation of soil quality, diminishing its water absorption capacity.

In reality, the water wreaks havoc both upstream and downstream, presenting a clear situation before us.

Case Study: Trial Bore in Flood-Prone Haryana

At SILVERON, we recognize the tangible and intangible losses incurred due to flooding in India, seeing it as an immeasurable national setback. We recognize the challenges of rapid infiltration posed by limited soil permeability or impermeable layers. We have proposed a strategic solution involving the implementation of drilling recharge shafts.

Our well-established design not only facilitates surface water infiltration but also intercepts subsurface flow, contributing to the replenishment of groundwater levels. The unlined bore design of our recharge shaft enhances its effectiveness in checking subsurface water.

Once water finds an easy path through the shaft, it establishes a regular route, attracting more water towards it. By enhancing the rate at which water permeates the ground, our solution holds the potential to significantly mitigate the impact of flooding.

We conducted a trial bore to test our shaft design in challenging flood management conditions, despite our confidence and experience.

As part of our social responsibility, we installed a Trial Recharge Shaft, at our own cost, in the flood-prone plains of Haryana. These plains experience annual inundation during monsoon as they sit below the mountains of Himachal Pradesh.

Our Endeavor

  1. We drilled the trial bore to appropriate depth to take advantage of soil strata having good absorption capacity and developed the recharge shaft following our standard basic design.
  • We deployed custom-designed Hume pipes, with a special 3 feet diameter and 8 feet length. These pipes featured holes of varying diameters (2, 4, and 6 inches) to facilitate water entry into the Recharge Shaft. Positioned at an 8 ft. length, 5 ft. of the pipe submerged into the ground, with 2-inch diameter holes positioned about 6 inches above the ground. Hole sizes are arranged in increasing order, considering the diminishing quantity of suspended silt as the water level rises.
  • A wire mesh barricade, standing at a height of 3 ft., was grouted around the Hume pipe, 3 feet away in all directions. We fill the space within the Hume pipe, between the pipe and the wire fencing with aggregate. This system prevents entry of suspended leaves, paper, polythene, and captures a portion of the suspended silt by reducing velocity. We then cover the top of the structure with wire mesh and aggregate.

These structures effectively mitigate the impact of running or collected rainwater, preventing serious damage to field soil or crops.

It’s noteworthy that each recharge shaft maintains a consistent intake speed, with observed likely intake flow around 200 cubic meters per day.

               Triumph is attainable solely through proactive endeavors.  

Preparing for the Worst: Mountain Lakes and Natural Catastrophes

Parts of Asia and South America have mountain regions prone to a high risk of flooding due to mountain lakes breaches and bursts.

In India, the Himalayas are home to a large number of glaciers. States like Jammu & Kashmir, Ladakh, Uttarakhand, Sikkim, Arunachal Pradesh, Assam and Himachal Pradesh are vulnerable to this phenomenon because of a large number of mountain lakes.

Mountain lakes often have base and walls made of debris and loose rocks. As the climate warms, new lakes are forming, and the dimensions of existing lakes are increasing in size, causing them to hold even larger quantities of water.

Over time, snow accumulated in mountainous regions compressed into glacial ice.  As temperatures rise, glaciers melt and carving large arena shaped depressions in the landscape. Retreating glaciers leave behind rocks and debris creating a wall or a natural dam to block the flow of water.

Various geological processes, such as tectonic activity, create natural depressions in mountains when movements in the Earth’s crust occur. Water flows from snow-melt, seasonal rainfall or cloud bursts replenish glacial lakes or mountain lakes  in elevated regions. 

Increasing changes in climate patterns, including more intense and frequent storms, altered precipitation patterns, and temperature variations are already influencing the hydrological cycle globally. The unique topography of mountains enhances the likelihood of notable phenomenon which leads to massive flash floods.

The dynamic mountain landscape, combined with natural and human-induced factors, contributes to the complexity of water flow patterns. These complex factors lead to increased volume and velocity of water flow from mountains to downstream plains. This causes flooding, potential damage to buildings and crops downstream.

Here is a clip from recordings done by our team from such locations.

Major Causes

  • Cloud Bursts: In mountainous regions, the terrain’s elevation forces moisture laden air to keep rising. As the air rises it cools, reaches its dew point and rapid condensation occurs. This process is known as orographic lifting. The primary cause of cloud bursts is the rapid condensation of moisture in the atmosphere, leading to sudden and very heavy rainfall in a short period over a localized area. This intense rainfall over a short duration leads to flash floods and landslides in mountainous regions.
  • Landslides: Due to combination of geological, climatic, and human-related factors, landslides are evidently the most common and devastating occurrences in the mountains. Some factors which facilitate landslides are:
    • Intense or prolonged periods of rainfall or rapidly melting snow that can saturate the soil quickly. This increased groundwater fluctuation can reduce soil cohesion, making it more prone to landslides, particularly along steep slopes.
    • Seismic activity, causing movements and adjustments due to tectonic forces both in the earthquake-prone areas and even in areas away from major fault lines. Seismic activity causes rocks and soil to lose stability and potentially trigger landslides.
    • Human actions like oil and gas extraction, mining and construction of reservoirs also contribute to low-level seismic activity. Vegetation helps absorb and slow down water runoff. Deforestation alters the natural stability of mountain slopes and leads to increased runoff. 


Early warning systems and effective water management strategies can significantly reduce the magnitude of devastation caused by sudden downstream flooding and runoff.

As proactive preventive measures, expenses associated with such efforts are relatively inconsequential when compared to the expenditures involved in disaster management efforts. Such disasters lead to an incalculable loss of livestock, crops, homes and human lives.

Satellite pictures and drone cameras can aid in studying and monitoring potential landslide-prone areas, facilitating appropriate land-use planning to mitigate the risk of landslides in mountainous regions.                                                                                           

Regular mapping and monitoring of water bodies in mountainous regions, along with coordinated and controlled releases of water from reservoirs, are crucial measures to reduce the ferocity of floods in downstream areas.

We must prioritize preventative measures at the point of origin. This will have the maximum impact on the magnitude of the problem. Consider measures like removing encroachments and clearing the natural flow path to facilitate the free movement of water.

We can gradually reduce a slope without resorting to permanent civil work by using loose boulders and pebbles. To reduce flow velocity, we can create multiple small dikes in the flow path using loose boulders and pebbles.

Water flows from the high mountains do not just affect certain areas. These massive quantities of water ultimately reach from mountains to the level ground of the plains. Here, the water stands there for weeks, destroying crop in the fields.

Here are some observations of this situation in parts of Haryana adjacent to Himachal Pradesh in June-July 2023.

The calmer water which manages to reach the plains should not be allowed to spoil the crop by flooding, stagnating or as run off. This water instead it should be utilized in recharging the ground water aquifers by designing appropriate Rain Water Harvesting systems. This effort will not only improve the water table but will also improve the ground water quality.