Percolation near Dongargaon
pt-14 · 20.9542, 79.9629 · PIN 441808
Contributing catchment 7.49 km² · at a 3 m bund it impounds 1,096 thousand m³ over 106 ha · design monsoon yield 2,035 thousand m³ · soil HSG-C (clay 38%).
In plain words
A new tank site on a nala near Dongargaon with a 7.5 km² catchment and — unusually — almost no one nearby: the nearest building is close to 2 km away, so nothing would be displaced. The sensors track the monsoon flow together (correlation 0.65), and the catchment comfortably fills the design.
What to build
Build a new percolation tank. No settlement is displaced, but a 3 m bund would submerge roughly 106 ha, so the flooded land use — cropland or forest — must be surveyed and cleared before sanction.
Why here
The lighter HSG-C soil supports genuine recharge (about a third of storage percolates), the catchment fills the design in a normal monsoon, and the absence of settlement makes this a rare low-conflict place to site a substantial recharge structure.
How
Ground-truth the submergence land use and the pour point, then construct the tank and weir; the large flooded area means the bund height should be tuned to the land actually available.
The delta — now vs after
From a nala whose flow runs off unused, to a substantial recharge and storage tank that serves Dongargaon without displacing a single household — provided the flooded land is confirmed unbuilt.
What it delivers · indicative
Indicative benefit at a 3 m bund (DEM area-capacity at 3 m bund) under standard norms (irrigation ~5 TCM/ha; drinking 150 lpcd). Recharge is limited on HSG-D clay (35% of storage). Actual yield varies with monsoon reliability, seepage and siltation.
Incremental over today · the net-new gain, from the 4-year record
≈ 1,096 thousand m³ of net-new water · 219 ha irrigable · 19,927 drinking person-years.
full design storage — no structure holds water here today.
Why this site
Sited where soil is lighter (HSG-C) or fractures raise infiltration — a percolation tank turns runoff into recharge rather than surface storage.
Seasonal water extent · dual-sensor
Radar (S1, 48 passes) fills the monsoon gap that cloud hides from optical (S2, 38 scenes). Radar peak vs summer low: 3.6 → 0 ha, a 3.6 ha annual draw-down — the storage renovation recovers.
Area-capacity (DEM, 30 m) · gross storage by bund height
Cross-witness & confidence — independent corroboration
Two sensors track together
Optical (S2) and radar (S1) rise and fall together with correlation r = 0.65 across 38 paired months. Absolute extents match 0% — they differ by sensor physics on a flowing nala, so the shared rhythm is the witness, not the magnitude.
Nala flow (new-build site)
No existing lake here — expected for a new structure. Sensors show only a weak flow signal in the nala; nearest mapped lake is 3,538 m away.
Land acquisition (submergence)
A 3 m bund would submerge 106 ha — the land to be acquired. Cost & consent scale with this.
Displacement witness — real building footprints
No structures in footprintIn the submergence footprint
0
buildings within the 580 m design-submergence radius (106 ha pond at 3 m).
Nearest structure
1,971 m
to the closest mapped building.
Within 500 m
0
buildings in the influence ring.
Overture Maps buildings 2026-05-20.0 (union of OSM / Google Open Buildings / Microsoft / Esri), Bhandara admin_code=506. A desktop displacement screen — precedes, not replaces, cadastral (7/12) verification.
Reconnaissance context & access — Ola + Google Places
Nearest habitation
Dongargaon
1,281 m away · PIN 441808
Nearest landmark
441808
Schools within 2 km
3
nearest 1,279 m
Health within 2 km
7
nearest 1,281 m
Google Places (New) searchNearby + Ola Maps Places nearbysearch · reconnaissance-grade. Independent witness to the buildings displacement layer — dense amenities near a site corroborate high displacement. Does not replace cadastral 7/12 records, geotechnical bores or a level survey.
Human pressure — land-cover change (2022 → 2026)
Stable land coverVegetation (NDVI) change
+0.044
28 ha lost · 131 ha gained over 1,828 ha land
Built-up (NDBI) change
20.9 ha
new built-up / bare (construction proxy)
Window
2022-11..2023-02 (8 scenes)
→ 2025-11..2026-02 (8 scenes)
Sentinel-2 L2A dry-season MEDIAN composites (2022-23 vs 2025-26), water-masked; NDVI+NDBI change screen — not cadastral or DEM cut/fill
DPR-grade desktop hydrology from Copernicus GLO-30 (30 m) + ISRIC SoilGrids + ESA WorldCover; water extent from Sentinel-2 L2A MNDWI (optical) and Sentinel-1 GRD VV radiometrically calibrated to σ⁰ (DN²/sigmaNought² from the product calibration LUT, GCP thin-plate-spline geocoded, open water at σ⁰ < −17 dB; thermal-noise floor not subtracted). A desktop assessment that precedes — not replaces — the statutory ground & geotechnical survey.