diff --git a/index.html b/index.html
index 905358ba..5c56fc6d 100644
--- a/index.html
+++ b/index.html
@@ -1854,7 +1854,7 @@
             <input id="renderOcean" class="checkbox" type="checkbox">
             <label for="renderOcean" class="checkbox-label">Render ocean cells</label>
           </div>
-          <div data-tip="Allow water flow to change heights on heightmap edit completion">
+          <div id="changeHeightsBox" data-tip="Regenerate rivers and allow water flow to slightly change heights">
             <input id="changeHeights" class="checkbox" type="checkbox" checked>
             <label for="changeHeights" class="checkbox-label">Allow water erosion</label>
           </div>
diff --git a/modules/river-generator.js b/modules/river-generator.js
index 7f4bbe0b..284ee98b 100644
--- a/modules/river-generator.js
+++ b/modules/river-generator.js
@@ -262,7 +262,7 @@
       r.type = r.parent && !(r.i%6) ? small ? "Branch" : "Fork" : small ? rw(smallType) : "River";
     }
 
-    return;
+    //return;
     const basins = [...(new Set(pack.rivers.map(r=>r.basin)))];
     const colors = getColors(basins.length);
     basins.forEach((b,i) => {
diff --git a/modules/ui/heightmap-editor.js b/modules/ui/heightmap-editor.js
index d645cd3f..b2f9b527 100644
--- a/modules/ui/heightmap-editor.js
+++ b/modules/ui/heightmap-editor.js
@@ -66,6 +66,9 @@ function editHeightmap() {
     applyTemplate.style.display = type === "keep" ? "none" : "inline-block";
     convertImage.style.display = type === "keep" ? "none" : "inline-block";
 
+    // hide erosion checkbox if mode is Keep
+    changeHeightsBox.style.display = type === "keep" ? "none" : "inline-block";
+
     // show finalize button
     if (!sessionStorage.getItem("noExitButtonAnimation")) {
       sessionStorage.setItem("noExitButtonAnimation", true);
@@ -212,10 +215,7 @@ function editHeightmap() {
     // assign pack data to grid cells
     const l = grid.cells.i.length;
     const biome = new Uint8Array(l);
-    const conf = new Uint8Array(l);
-    const fl = new Uint16Array(l);
     const pop = new Uint16Array(l);
-    const r = new Uint16Array(l);
     const road = new Uint16Array(l);
     const crossroad = new Uint16Array(l);
     const s = new Uint16Array(l);
@@ -225,14 +225,16 @@ function editHeightmap() {
     const culture = new Uint16Array(l);
     const religion = new Uint16Array(l);
 
+    // rivers data, stored only if changeHeights is unchecked
+    const fl = new Uint16Array(l);
+    const r = new Uint16Array(l);
+    const conf = new Uint8Array(l);
+
     for (const i of pack.cells.i) {
       const g = pack.cells.g[i];
       biome[g] = pack.cells.biome[i];
-      conf[g] = pack.cells.conf[i];
       culture[g] = pack.cells.culture[i];
-      fl[g] = pack.cells.fl[i];
       pop[g] = pack.cells.pop[i];
-      r[g] = pack.cells.r[i];
       road[g] = pack.cells.road[i];
       crossroad[g] = pack.cells.crossroad[i];
       s[g] = pack.cells.s[i];
@@ -240,6 +242,12 @@ function editHeightmap() {
       province[g] = pack.cells.province[i];
       burg[g] = pack.cells.burg[i];
       religion[g] = pack.cells.religion[i];
+
+      if (!changeHeights.checked) {
+        fl[g] = pack.cells.fl[i];
+        r[g] = pack.cells.r[i];
+        conf[g] = pack.cells.conf[i];
+      }
     }
 
     // do not allow to remove land with burgs
@@ -289,23 +297,30 @@ function editHeightmap() {
     pack.cells.province = new Uint16Array(n);
     pack.cells.culture = new Uint16Array(n);
     pack.cells.religion = new Uint16Array(n);
-
-    pack.cells.r = new Uint16Array(n);
-    pack.cells.conf = new Uint8Array(n);
-    pack.cells.fl = new Uint16Array(n);
     pack.cells.biome = new Uint8Array(n);
 
+    if (!changeHeights.checked) {
+      pack.cells.r = new Uint16Array(n);
+      pack.cells.conf = new Uint8Array(n);
+      pack.cells.fl = new Uint16Array(n);
+    }
+
     for (const i of pack.cells.i) {
       const g = pack.cells.g[i];
       const land = pack.cells.h[i] >= 20;
 
-      pack.cells.r[i] = r[g];
-      pack.cells.conf[i] = conf[g];
-      pack.cells.fl[i] = fl[g];
+      // check biome
       if (land && !biome[g]) pack.cells.biome[i] = getBiomeId(grid.cells.prec[g], grid.cells.temp[g]);
       else if (!land && biome[g]) pack.cells.biome[i] = 0;
       else pack.cells.biome[i] = biome[g];
 
+      // rivers data
+      if (!changeHeights.checked) {
+        pack.cells.r[i] = r[g];
+        pack.cells.conf[i] = conf[g];
+        pack.cells.fl[i] = fl[g];
+      }
+
       if (!land) continue;
       pack.cells.culture[i] = culture[g];
       pack.cells.pop[i] = pop[g];