Layer: Downstream Dependency Zones

Summary

This explorer layer marks broad downstream exposure zones connected to Nepal-origin river routes, covering agriculture, population, flood, dry-season-flow, sediment, and delta-sensitivity context.

Explorer label: Downstream dependency zones
Layer group: Hydrology and basin layers
Feature count: 5

Strategic downstream exposure zones for agriculture, population, floods, dry-season flow, sediment, and delta sensitivity.

What It Represents

This layer turns the route-to-ocean trace into a downstream stakes map. It marks broad regions where Nepal-linked river routes pass through dense agricultural plains, flood-sensitive corridors, and the Bangladesh delta system.

For the non-technical reading sequence, start with How To Read The Geopolitics Map. For the main synthesis, use Downstream River Geopolitics.

The five mapped zones are:

Zone	Main read
Eastern Uttar Pradesh Ghaghara-Gandak belt	Western and central Nepal-linked routes entering dense agricultural plains.
North Bihar Kosi-Gandak floodplain	High exposure to flood timing, sediment, agriculture, and dense settlement.
Bihar Ganges trunk zone	Shared Ganges corridor where separate Nepal-linked routes become a common downstream geography.
Padma-Meghna delta dependency zone	Bangladesh-scale delta exposure to upstream timing, sediment, and flood pulses.
Lower delta and Bay interface	Coastal-delta context for sediment, salinity, storm surge exposure, and delta stability.

How To Read It

Use these polygons as strategic context around the river route, not as precise service areas.

Important fields:

Field	How To Use It
`related_origin_routes`	Links each zone to the Nepal-origin route traces that pass into or through it.
`population_pressure`	Qualitative pressure class for map interpretation.
`agriculture_importance`	Qualitative agriculture relevance.
`dry_season_sensitivity`	Whether timing and dry-season support are strategically relevant.
`flood_sensitivity`	Whether monsoon flood timing and attenuation matter.
`sediment_sensitivity`	Whether sediment behavior should be part of the strategic read.
`delta_sensitivity`	Whether the zone is part of lower-delta vulnerability.
`strategic_read`	Plain-language interpretation for popups.

Coverage / Method

The layer is built as a five-zone polygon context layer in the downstream dependency map outputs. It links each zone to related Nepal-origin route traces and uses qualitative fields for population pressure, agriculture importance, dry-season sensitivity, flood sensitivity, sediment sensitivity, delta sensitivity, and popup reading context.

Caveats

This is not a hydrodynamic model, irrigation command map, population raster, crop-intensity map, or flood hazard model. It does not claim that Nepal controls total water availability in these zones.

The correct reading is: these are downstream exposure zones touched by Nepal-linked river routes where timing, sediment, flood behavior, and dry-season flow can become politically meaningful.