Drones for Watershed Management

Small and micro drones for watershed management can help turnaround and improve the success rate and future impact potential of multiple water conservation, irrigation, CCT, dams (etc.) projects. In this piece, we would see how ideaForge’s all-terrain high-endurance drones can help better manage our watersheds with lower runoff, higher percolation and minimal erosion/siltation.

Watershed management is an ecological-social-economic issue

Water is essential for survival. This is one of the most basic statements in the world. However, water scarcity has challenged us time and again. India receives 4% of the world’s freshwater to support 16% of the world’s population.

The water received through rainfall (as a part of the water cycle) is collected within watersheds. The water either flows downstream, seeps into the soil or evaporates. The seeping water adds to the ‘water table’ which recharges groundwater in wells and ponds. Downstream flowing water supports the ecological balance of the surroundings.

By definition, all of the world’s surface can be considered as a single watershed. However, based on realistic and impact assessment, watersheds are divided based on ridgelines. India’s watershed classification showcases around 3237 unique watersheds.

Watersheds are critical for irrigation and livelihood support for surrounding areas. This is far more impactful for primarily rain-fed regions. India has many such rain-fed regions. These regions deal with rain-related contingencies which lead to fluctuating incomes, harvest/yield shrinkages and wasted resources.

Challenges to proper watershed management

Watershed mismanagement leads to deterioration of the entire ecosystem. Excess runoff leads to wasted resources as lesser water percolates into the soil, in turn leading to a lower water table. This means that there’s less groundwater available in the natural and man-made reservoirs.

Furthermore, degradation of river valley surroundings (industrial, construction, grazing and agriculture use) increases water pollution through siltation and sedimentation. They also compromise the wetlands which act as natural water filters (through naturally-occurring biochemical reactions).

This leads to excess water pollution pushing towards the Total Maximum Daily Load (TMDL). TMDL is the threshold pollution limit wherein the downstream water is still consumable.

These are major reasons for watershed deterioration.

Let us take a look at the problem areas and specific problem statements in each area.

  1. Improper agricultural processes
    i. Improper or excessive cropping
    ii. Crop plantation on slopes or around nalas
  2. Forest mismanagement
    i. Illegal or unplanned deforestation/tree felling
    ii. Removal of plant coverage along steep slopes
    iii. Forest fires
  3. Grassland mismanagement
    i. High grazing
    ii. Soil compaction leading to reduced infiltration
  4. Mining and quarrying
    i. Contour destruction and slope exposure
  5. Improper construction activities
    i. Roads or building construction leading to sediment flow into drainage links/channels
  6. Lack of ecosystem awareness (among local participants)
    i. Continuing improper farming and water usage practices (like flood irrigation), etc.

Impact of watershed deterioration

  • Wasted runoff
  • Fast-running water (eroding soil and washing-out crops)
  • Polluted streams
  • Fast reservoir and water bodies siltation
  • Heavy sedimentation of water bodies – reduced water quality
  • Lower drainage in river valleys
  • Lower water table
  • Increased chances of drought and floods (including flash floods)

Drones for watershed management – The transformation point

ideaForge drones have been celebrated for their superior applications and implications on major defence, homeland security and industrial projects. They have been adopted by central and local authorities for watershed management.

Drones have come up as key catalysts and efficiency-enablers within the integrated or participatory watershed management approaches. Integrated is when the authorities leverage tech-backed innovation to plan, forecast, execute and sustain watershed management. Participatory is when (on top of the integrated approach activities) the authorities actively collaborate with NGOs, local government and people.

Drones have amplified the impact of various watershed management projects through key interventions and enablement. Here’s a broad overview of the same.

Drone-backed surveying and mapping for watershed management

ideaForge drones are Post-Processing Kinematic (PPK) enabled. This greatly enhances the timeliness, ease and spatiotemporal accuracy of surveying and mapping activities. These survey-grade Unmanned Aerial Vehicles (UAVs) ensure high-quality intelligence gathering with precision (down to even 5cm Ground Sampling Distance (GSD).

Before drone use, supervisors manually surveyed the slopes and relevant areas using basic dumpy levels and hydromarkers.

Let’s talk about the importance of spatiotemporal accuracy for a minute. Manual surveying takes a long time and is mostly dependent on publicly-available Geographic Information System (GIS) data.

Contour-lines, vegetative cover, slope dimensions, etc. tend to change over time. Here, dated GIS information or older numbers wouldn’t serve the purpose.

Continuous Contour Trenches (CCT) built through manual surveying may lead to breakage (of the CCTs due to excess water weight or wrong contour line mapping) leading to an overall imbalance within the watershed management project.

Drone-led ecological and economic investigation

Drones ensure spatiotemporal accuracy down to the centimetre with detailed cut and fill volumetric estimations. These drones help create accurate 3D Digital Elevation Models (DEM) and 3D contour profiles. Additionally, they give a detailed and real-time assessment with:

  • Real-time change detection around river banks (migration, erosion, sedimentation, etc.)
  • Change detection forest and vegetation cover mapping
  • Checking of farming, grazing, industrial, construction, etc. activities around the river banks
  • Historical referencing of all ecological and watershed related information in a consolidated and digital database (time and location stamped HD visual and thermal coverage)
  • Economic impact study of surrounding areas (effect on the livelihood of rain-fed regions)

These investigations form the basis for current and future watershed management plans.

There’s another big impact area for drones. Improper watershed management due to lack of (or inaccurately built) trenches, deforestation, slow water infiltration (into the ground) may result in flash floods.

Drones-led surveying and mapping help with accurate water table prediction, runoff estimations, and disaster mitigation (ensuring minimal impact due to landslides or loss of standing crop). The spatiotemporally accurate drone-data has become an integral part of the master plan for flood control.

Drone-enabled multipurpose watershed project management

Drones have clear and consistent applications for the planning, construction, operations, monitoring, and improvement of watershed-related projects. These projects can be connected to multiple storage structures, hydropower generation, irrigation planning and execution, etc.

Drones help align watershed project management with spatiotemporally accurate water tables and runoff projections. This is synced with the detailed 3D models (survey and mapping) checking river bank migration, erosion and wetland status (their regression or development).

Drones power through everything from the initial contour and drainage line mapping to accurate planning and overview of all CCT construction. They further help with slope analysis. All this ties-in with real-time weather and GIS data to predict the level of water that could be successfully collected and utilized.

This information and further drone-led surveying give strength to multi-purpose watershed (management) project planning. Drones enable orthomosaic-imagery and advanced photogrammetry to calculate the ideal maximum submergence area, volumetric estimation of water at different contour levels (lines), and the ideal dimensions of the dam or project structure.

Drone benefits | Endurance, coverage, accuracy, speed, replicability and availability

There are 3237 unique watersheds in the country. For many of these watersheds, manual surveying and planning form a bottleneck. This is worsened by the lack of qualified supervisors for on-site work.

Drones help these supervisors with remote site surveillance and even to establish a secure and live connection with all stakeholders. ideaForge’s high-endurance drones can improve the surveying and mapping speed and accuracy multi-fold. In actual cases, the surveyors were able to quickly evaluate existing trenches and plan successive CCTs with total precision. With drones, they were able to do all this in less than 1/6th of the time (compared to the time taken before drones).

Drone-led watershed management is replicable and available. This means that the process can be accurately recreated and propagated, without any bottleneck or hiccup, anywhere in the country.

All these points and efforts go beyond tech-applications. Quality and sustained watershed management is the biggest socio-economic-ecological booster. We should leverage the right tech, drones, in this case, to improve upon the projects and the connected livelihoods.



August 2020

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