From 93f37d874e64b98e50aed231acc22f6fa9cb67a2 Mon Sep 17 00:00:00 2001
From: Codex <codex@geointel.local>
Date: Wed, 15 Jul 2026 22:35:48 +0200
Subject: [PATCH] Separate flood hazards from surface water theme

---
 backend/tests/test_sprint208_vmm_flood_hazard.py | 2 ++
 frontend/src/components/map/MapWorkspace.tsx     | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/backend/tests/test_sprint208_vmm_flood_hazard.py b/backend/tests/test_sprint208_vmm_flood_hazard.py
index 7473c402..d8543475 100644
--- a/backend/tests/test_sprint208_vmm_flood_hazard.py
+++ b/backend/tests/test_sprint208_vmm_flood_hazard.py
@@ -366,3 +366,5 @@ def test_flood_hazard_runtime_contract_is_packaged() -> None:
     assert "COPY scripts/provision_mol_flood_hazards.py" in dockerfile
     assert "Overstromingsscenario" in frontend
     assert "floodHazardImageUrl" in frontend
+    assert "dataset.source_name === 'vmm_flood_hazard'" in frontend
+    assert "return theme.id === 'flood_hazard'" in frontend
diff --git a/frontend/src/components/map/MapWorkspace.tsx b/frontend/src/components/map/MapWorkspace.tsx
index f2a5a61b..93440b56 100644
--- a/frontend/src/components/map/MapWorkspace.tsx
+++ b/frontend/src/components/map/MapWorkspace.tsx
@@ -147,6 +147,15 @@ function datasetSearchText(dataset: DatasetCreateResponse): string {
 }
 
 function datasetMatchesTheme(dataset: DatasetCreateResponse, theme: DataTheme): boolean {
+  // Governed raster products have one unambiguous semantic theme. Matching
+  // them by generic substrings (for example "water" in "waterdiepte") would
+  // make a flood scenario replace the permanent surface-water layer.
+  if (dataset.source_name === 'vmm_flood_hazard') {
+    return theme.id === 'flood_hazard'
+  }
+  if (dataset.source_name === 'digitaal_vlaanderen_dhmv') {
+    return theme.id === 'elevation'
+  }
   const searchText = datasetSearchText(dataset)
   return theme.tokens.some((token) => searchText.includes(token))
 }