diff --git a/tests/domain/build-runtime-scene.test.ts b/tests/domain/build-runtime-scene.test.ts
index b56a17e0..257d96fa 100644
--- a/tests/domain/build-runtime-scene.test.ts
+++ b/tests/domain/build-runtime-scene.test.ts
@@ -733,7 +733,8 @@ describe("buildRuntimeSceneFromDocument", () => {
           colorHex: "#2f79c4",
           surfaceOpacity: 0.7,
           waveStrength: 0.35,
-          foamContactLimit: 6
+          foamContactLimit: 6,
+          surfaceDisplacementEnabled: false
         }
       }
     });
diff --git a/tests/domain/create-box-brush.command.test.ts b/tests/domain/create-box-brush.command.test.ts
index 2464704a..8e6b631b 100644
--- a/tests/domain/create-box-brush.command.test.ts
+++ b/tests/domain/create-box-brush.command.test.ts
@@ -296,7 +296,8 @@ describe("box brush commands", () => {
             colorHex: "#3a7dc2",
             surfaceOpacity: 0.65,
             waveStrength: 0.4,
-            foamContactLimit: 6
+            foamContactLimit: 6,
+            surfaceDisplacementEnabled: false
           }
         }
       })
@@ -308,7 +309,8 @@ describe("box brush commands", () => {
         colorHex: "#3a7dc2",
         surfaceOpacity: 0.65,
         waveStrength: 0.4,
-        foamContactLimit: 6
+        foamContactLimit: 6,
+        surfaceDisplacementEnabled: false
       }
     });
 
@@ -324,7 +326,8 @@ describe("box brush commands", () => {
         colorHex: "#3a7dc2",
         surfaceOpacity: 0.65,
         waveStrength: 0.4,
-        foamContactLimit: 6
+        foamContactLimit: 6,
+        surfaceDisplacementEnabled: false
       }
     });
   });
diff --git a/tests/domain/scene-document-validation.test.ts b/tests/domain/scene-document-validation.test.ts
index 8a8255b3..dfa4f502 100644
--- a/tests/domain/scene-document-validation.test.ts
+++ b/tests/domain/scene-document-validation.test.ts
@@ -552,7 +552,8 @@ describe("validateSceneDocument", () => {
       water: {
         colorHex: "#3a7dc2",
         surfaceOpacity: 0.6,
-        waveStrength: 0.3
+        waveStrength: 0.3,
+        surfaceDisplacementEnabled: false
       }
     };
     (invalidWaterBrush as any).volume = {
@@ -599,6 +600,10 @@ describe("validateSceneDocument", () => {
           code: "invalid-box-water-wave-strength",
           path: "brushes.brush-invalid-volume-water.volume.water.waveStrength"
         }),
+        expect.objectContaining({
+          code: "invalid-box-water-surface-displacement-enabled",
+          path: "brushes.brush-invalid-volume-water.volume.water.surfaceDisplacementEnabled"
+        }),
         expect.objectContaining({
           code: "invalid-box-fog-color",
           path: "brushes.brush-invalid-volume-fog.volume.fog.colorHex"
diff --git a/tests/domain/water-material.test.ts b/tests/domain/water-material.test.ts
index 8730d935..705f7c60 100644
--- a/tests/domain/water-material.test.ts
+++ b/tests/domain/water-material.test.ts
@@ -608,8 +608,9 @@ describe("water material helpers", () => {
     expect(material.uniforms["fogDensity"]).toBeDefined();
     expect(material.uniforms["surfaceOpacity"]?.value).toBeGreaterThan(0.14);
     expect(material.uniforms["waveStrength"]?.value).toBe(0.35);
+    expect(material.uniforms["surfaceDisplacementEnabled"]?.value).toBe(0);
     expect(material.uniforms["isTopFace"]?.value).toBe(1);
-    expect(material.vertexShader).not.toContain("transformed.y +=");
+    expect(material.vertexShader).toContain("surfaceDisplacementEnabled");
     expect(result.contactPatchesUniform?.value).toHaveLength(MAX_BOX_BRUSH_WATER_FOAM_CONTACT_LIMIT);
     expect(result.contactPatchShapesUniform?.value).toHaveLength(MAX_BOX_BRUSH_WATER_FOAM_CONTACT_LIMIT);
     expect(result.reflectionTextureUniform).not.toBeNull();
diff --git a/tests/serialization/scene-document-json.test.ts b/tests/serialization/scene-document-json.test.ts
index 17c8b407..a8f46167 100644
--- a/tests/serialization/scene-document-json.test.ts
+++ b/tests/serialization/scene-document-json.test.ts
@@ -151,7 +151,8 @@ describe("scene document JSON", () => {
           colorHex: "#2f79c4",
           surfaceOpacity: 0.65,
           waveStrength: 0.35,
-          foamContactLimit: 9
+          foamContactLimit: 9,
+          surfaceDisplacementEnabled: true
         }
       }
     });
@@ -308,7 +309,8 @@ describe("scene document JSON", () => {
     expect(migratedDocument.brushes["brush-water-legacy"]?.volume).toEqual({
       mode: "water",
       water: expect.objectContaining({
-        foamContactLimit: 24
+        foamContactLimit: 24,
+        surfaceDisplacementEnabled: false
       })
     });
   });
diff --git a/tests/unit/underwater-fog.test.ts b/tests/unit/underwater-fog.test.ts
index 41de8e40..d3da7b5d 100644
--- a/tests/unit/underwater-fog.test.ts
+++ b/tests/unit/underwater-fog.test.ts
@@ -28,7 +28,7 @@ describe("resolveUnderwaterFogState", () => {
 
     expect(fogState).not.toBeNull();
     expect(fogState?.colorHex).toBe("#347aa0");
-    expect(fogState?.density ?? 0).toBeCloseTo(0.03352, 5);
+    expect(fogState?.density ?? 0).toBeCloseTo(0.08295, 5);
   });
 
   it("does not enable fog when the camera is not submerged", () => {
diff --git a/tests/unit/water-volume.integration.test.tsx b/tests/unit/water-volume.integration.test.tsx
index 33a5de39..8d2166e7 100644
--- a/tests/unit/water-volume.integration.test.tsx
+++ b/tests/unit/water-volume.integration.test.tsx
@@ -100,7 +100,8 @@ describe("water volume integration", () => {
           colorHex: "#4da6d9",
           surfaceOpacity: 0.55,
           waveStrength: 0.35,
-          foamContactLimit: 6
+          foamContactLimit: 6,
+          surfaceDisplacementEnabled: false
         }
       }
     });
@@ -144,7 +145,8 @@ describe("water volume integration", () => {
           colorHex: "#12a4ff",
           surfaceOpacity: 0.55,
           waveStrength: 0.35,
-          foamContactLimit: 6
+          foamContactLimit: 6,
+          surfaceDisplacementEnabled: false
         }
       });
     });