Percolation near Panjara
pt-12 · 21.2509, 79.7877 · PIN 441905
Contributing catchment 7.62 km² · at a 2 m bund it impounds 225 thousand m³ over 37 ha · design monsoon yield 3,736 thousand m³ · soil HSG-C (clay 39%).
In plain words
A percolation-tank site near Panjara on lighter HSG-C soil — genuinely recharge-capable — with a 7.6 km² catchment. The sensors agree only weakly (correlation 0.23) and the water is small, so the water evidence is modest. A 3 m bund would flood houses, so it is sized to 2 m; twelve buildings still fall within that footprint.
What to build
Survey the twelve structures — and test whether an even lower bund clears them — and confirm the flow.
Why here
HSG-C soil makes recharge worthwhile (about a third of storage percolates), but the weak water signal and the twelve nearby structures make this a genuine survey question.
How
Cadastral + ground check of the twelve structures; recharge and flow confirmation across a monsoon.
The delta — now vs after
A settlement-clearing tank adds ~225 thousand m³ and real recharge for Panjara; if the land or flow will not clear, drop it.
What it delivers · indicative
Indicative benefit at a 2 m bund (DEM area-capacity at 2 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
≈ 225 thousand m³ of net-new water · 45 ha irrigable · 4,091 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: 2.9 → 0 ha, a 2.9 ha annual draw-down — the storage renovation recovers.
Area-capacity (DEM, 30 m) · gross storage by bund height
Design point stepped down to 2 m: a full 3 m bund here would flood settlement, so the site is sized to the largest height that clears it while the catchment still fills the pond.
Cross-witness & confidence — independent corroboration
Two sensors track together
Optical (S2) and radar (S1) rise and fall together with correlation r = 0.23 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 confirm a monsoon flow pulse in the nala; nearest mapped lake is 4,196 m away.
Land acquisition (submergence)
A 3 m bund would submerge 105 ha — the land to be acquired. Cost & consent scale with this.
⚠ catchment likely includes a through-flowing nala — verify pour point
Displacement witness — real building footprints
Several structures — survey neededIn the submergence footprint
12
buildings within the 344 m design-submergence radius (37 ha pond at 2 m).
Nearest structure
105 m
to the closest mapped building.
Within 500 m
23
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
Panjara
667 m away · PIN 441905
Nearest landmark
Palora
Schools within 2 km
3
nearest 1,382 m
Health within 2 km
2
nearest 1,409 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
+0.005
122 ha lost · 90 ha gained over 1,854 ha land
Built-up (NDBI) change
72 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.