Check dam near Silegaon
cd-14 · 21.4343, 79.8481 · Tumsar taluka · PIN 441915
Contributing catchment 116.45 km² · at a 2 m bund it impounds 158 thousand m³ over 28 ha · design monsoon yield 54,578 thousand m³ · soil HSG-D (clay 40%).
In plain words
A check-dam site near Silegaon (Tumsar) on a large 116 km² catchment where the two sensors track the monsoon flow moderately (correlation 0.53). A full 3 m bund would flood houses, so the site is sized to a 2 m bund — even then, eight buildings fall within the footprint (nearest ~120 m).
What to build
Survey the eight structures and verify the pour point; build a 2 m check dam / nala bund if the land clears.
Why here
The big catchment makes monsoon runoff abundant (the 2 m pond fills many times over); the open questions are the eight structures and the usual large-catchment check that the reach is a harvestable nala, not a through-flowing river.
How
Cadastral (7/12) overlay and ground survey of the eight structures; confirm the pour point and through-flow.
The delta — now vs after
A 2 m bund clear of the houses adds ~160 thousand m³ of new monsoon storage for Silegaon; if the land or through-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 (12% of storage). Actual yield varies with monsoon reliability, seepage and siltation.
Incremental over today · the net-new gain, from the 4-year record
≈ 158 thousand m³ of net-new water · 32 ha irrigable · 2,873 drinking person-years.
full design storage — no structure holds water here today.
Why this site
Sited on an order-4 nala with a 116.5 km² contributing catchment and gentle grade — a nala/check dam impounds monsoon runoff on the clay lowlands where infiltration is low.
Seasonal water extent · dual-sensor
Radar (S1, 48 passes) fills the monsoon gap that cloud hides from optical (S2, 37 scenes). Radar peak vs summer low: 6.1 → 0 ha, a 6.1 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 = 0.53 across 37 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 6,812 m away.
Land acquisition (submergence)
A 3 m bund would submerge 88 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
8
buildings within the 296 m design-submergence radius (28 ha pond at 2 m).
Nearest structure
117 m
to the closest mapped building.
Within 500 m
48
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
Silegaon
993 m away · Tumsar taluka · PIN 441915
Nearest landmark
Wahini
Schools within 2 km
2
nearest 487 m
Health within 2 km
2
nearest 666 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
+0.026
103 ha lost · 183 ha gained over 1,806 ha land
Built-up (NDBI) change
66.6 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.