The Protection Gap in Dhaka's Urban Planning
A geospatial assessment reveals a critical divergence between the ambitious 2022-2035 Detailed Area Plan (DAP) and on-the-ground spatial realities.
Regulatory Deficit (P_GAP)
Of 13,721 Ha of mapped waterbodies, 5,758 Ha lack explicit legal protection in the current zoning plan.
The Urban-Hydrological Conflict
Dhaka is facing a "Planning Paradox" where formal mandates are undermined by aggressive market-led growth.
Systemic Encroachment
Aggressive land reclamation and infilling have led to the loss of critical flood flow zones. This is not accidental but driven by high economic rent.
Regulatory Limbo
Nearly 42% of waterbodies exist physically but are absent from conservation maps. This "limbo" allows developers to bypass environmental laws legally.
Flood Vulnerability
The degradation of the "Blue Network" compromises flood retention capacity, exacerbating waterlogging and the Urban Heat Island effect.
Advanced Planning Tools
To quantify the invisible gap, this study moved beyond qualitative critique, employing rigorous geospatial frameworks to audit the city's planning performance.
GIS Geometric Overlay
Calculated the P_GAP by overlaying digitized waterbody layers against the official DAP conservation zoning maps.
MCDM Framework
Multi-Criteria Decision Making used to generate a Vulnerability Index (VI), weighting proximity to infrastructure and land value.
LULC Change Detection
Utilized Sentinel-2 satellite imagery to detect post-2022 built-up expansion into designated buffer zones.
Methodology Workflow
Spatial Evidence & Findings
The analysis uncovered a staggering 42,334 Ha "High Conflict Zone", representing areas where conservation mandates clash with high-value development pressure.
| Indicator | Symbol | Area (Ha) | Percentage |
|---|---|---|---|
| Total Waterbody Area | A_Total | 13,721.34 | 100.00% |
| Protected Waterbody Area | A_Protected | 7,962.96 | 58.03% |
| Unprotected Area (GAP) | A_Unprotected | 5,758.38 | 41.97% |
| Total High Conflict Area | A_Conflict | 42,334.30 | N/A |
The Spatial Gap
Shows the 5,758 Ha of waterbodies missing from the official conservation map, mostly in peripheral growth zones.
Conflict Zones
Maps the 42,334 Ha area where high land value overlaps with ecological buffers, indicating extreme encroachment risk.
Strategic Policy Recommendations
To bridge the policy-practice gap, we propose a multi-tiered enforcement strategy backed by the overarching Water Bodies Conservation Act (2000).
Immediate Reclassification
The 5,758 Ha of "Unprotected" waterbodies must be immediately designated as ECA_Critical. This provides the highest legal protection superseding local zoning.
Conservation Tax
Implement a punitive tax (approx. 300% of land value) on developments within buffer zones. This creates an economic disincentive strong enough to counter real estate profits.
Hydrological Task Force (HETF)
Form a high-power inter-agency body (RAJUK, DNCC, DoE) to eliminate institutional fragmentation and ensure unified enforcement of conservation boundaries.
Adaptive Real-Time Monitoring
Operationalize the GIS/MCDM methodology for continuous monitoring of the 200m buffer zones, allowing for adaptive, spatially-explicit enforcement actions.