diff --git a/index.html b/index.html
index fc388af6..85c9b2bd 100644
--- a/index.html
+++ b/index.html
@@ -541,6 +541,7 @@
               id="toggleRivers"
               data-tip="Rivers: click to toggle, drag to raise or lower the layer. Ctrl + click to edit layer style"
               data-shortcut="V"
+              class="buttonoff"
               onclick="toggleRivers(event)"
             >
               Ri<u>v</u>ers
@@ -8032,7 +8033,6 @@
     <script src="modules/names-generator.js?v=1.87.14"></script>
     <script src="modules/cultures-generator.js?v=1.99.05"></script>
     <script src="modules/renderers/draw-state-labels.js?v=1.103.00"></script>
-    <script src="modules/renderers/draw-borders.js?v=1.103.00"></script>
     <script src="modules/burgs-and-states.js?v=1.103.00"></script>
     <script src="modules/provinces-generator.js?v=1.103.00"></script>
     <script src="modules/routes-generator.js?v=1.99.04"></script>
@@ -8101,5 +8101,8 @@
     <script defer src="modules/io/load.js?v=1.100.00"></script>
     <script defer src="modules/io/cloud.js?v=1.99.00"></script>
     <script defer src="modules/io/export.js?v=1.100.00"></script>
+
+    <script defer src="modules/renderers/draw-borders.js?v=1.103.00"></script>
+    <script defer src="modules/renderers/draw-heightmap.js?v=1.103.00"></script>
   </body>
 </html>
diff --git a/main.js b/main.js
index 8120e591..295d57f8 100644
--- a/main.js
+++ b/main.js
@@ -639,7 +639,6 @@ async function generate(options) {
     drawCoastline();
 
     Rivers.generate();
-    drawRivers();
     Lakes.defineGroup();
     Biomes.define();
 
diff --git a/modules/renderers/draw-heightmap.js b/modules/renderers/draw-heightmap.js
new file mode 100644
index 00000000..97505c8d
--- /dev/null
+++ b/modules/renderers/draw-heightmap.js
@@ -0,0 +1,142 @@
+"use strict";
+
+function drawHeightmap() {
+  TIME && console.time("drawHeightmap");
+
+  const ocean = terrs.select("#oceanHeights");
+  const land = terrs.select("#landHeights");
+
+  ocean.selectAll("*").remove();
+  land.selectAll("*").remove();
+
+  const paths = new Array(101);
+  const {cells, vertices} = grid;
+  const used = new Uint8Array(cells.i.length);
+  const heights = Array.from(cells.i).sort((a, b) => cells.h[a] - cells.h[b]);
+
+  // ocean cells
+  const renderOceanCells = Boolean(+ocean.attr("data-render"));
+  if (renderOceanCells) {
+    const skip = +ocean.attr("skip") + 1 || 1;
+    const relax = +ocean.attr("relax") || 0;
+    lineGen.curve(d3[ocean.attr("curve") || "curveBasisClosed"]);
+
+    let currentLayer = 0;
+    for (const i of heights) {
+      const h = cells.h[i];
+      if (h > currentLayer) currentLayer += skip;
+      if (h < currentLayer) continue;
+      if (currentLayer >= 20) break;
+      if (used[i]) continue; // already marked
+      const onborder = cells.c[i].some(n => cells.h[n] < h);
+      if (!onborder) continue;
+      const vertex = cells.v[i].find(v => vertices.c[v].some(i => cells.h[i] < h));
+      const chain = connectVertices(cells, vertices, vertex, h, used);
+      if (chain.length < 3) continue;
+      const points = simplifyLine(chain, relax).map(v => vertices.p[v]);
+      if (!paths[h]) paths[h] = "";
+      paths[h] += round(lineGen(points));
+    }
+  }
+
+  // land cells
+  {
+    const skip = +land.attr("skip") + 1 || 1;
+    const relax = +land.attr("relax") || 0;
+    lineGen.curve(d3[land.attr("curve") || "curveBasisClosed"]);
+
+    let currentLayer = 20;
+    for (const i of heights) {
+      const h = cells.h[i];
+      if (h > currentLayer) currentLayer += skip;
+      if (h < currentLayer) continue;
+      if (currentLayer > 100) break; // no layers possible with height > 100
+      if (used[i]) continue; // already marked
+      const onborder = cells.c[i].some(n => cells.h[n] < h);
+      if (!onborder) continue;
+
+      const startVertex = cells.v[i].find(v => vertices.c[v].some(i => cells.h[i] < h));
+      const chain = connectVertices(cells, vertices, startVertex, h, used);
+      if (chain.length < 3) continue;
+
+      const points = simplifyLine(chain, relax).map(v => vertices.p[v]);
+      if (!paths[h]) paths[h] = "";
+      paths[h] += round(lineGen(points));
+    }
+  }
+
+  // render paths
+  for (const height of d3.range(0, 101)) {
+    const group = height < 20 ? ocean : land;
+    const scheme = getColorScheme(group.attr("scheme"));
+
+    if (height === 0 && renderOceanCells) {
+      // draw base ocean layer
+      group
+        .append("rect")
+        .attr("x", 0)
+        .attr("y", 0)
+        .attr("width", graphWidth)
+        .attr("height", graphHeight)
+        .attr("fill", scheme(1));
+    }
+
+    if (height === 20) {
+      // draw base land layer
+      group
+        .append("rect")
+        .attr("x", 0)
+        .attr("y", 0)
+        .attr("width", graphWidth)
+        .attr("height", graphHeight)
+        .attr("fill", scheme(0.8));
+    }
+
+    if (paths[height] && paths[height].length >= 10) {
+      const terracing = group.attr("terracing") / 10 || 0;
+      const color = getColor(height, scheme);
+
+      if (terracing) {
+        group
+          .append("path")
+          .attr("d", paths[height])
+          .attr("transform", "translate(.7,1.4)")
+          .attr("fill", d3.color(color).darker(terracing))
+          .attr("data-height", height);
+      }
+      group.append("path").attr("d", paths[height]).attr("fill", color).attr("data-height", height);
+    }
+  }
+
+  // connect vertices to chain: specific case for heightmap
+  function connectVertices(cells, vertices, start, h, used) {
+    const n = cells.i.length;
+    const chain = []; // vertices chain to form a path
+    for (let i = 0, current = start; i === 0 || (current !== start && i < 20000); i++) {
+      const prev = chain[chain.length - 1]; // previous vertex in chain
+      chain.push(current); // add current vertex to sequence
+      const c = vertices.c[current]; // cells adjacent to vertex
+      c.filter(c => cells.h[c] === h).forEach(c => (used[c] = 1));
+      const c0 = c[0] >= n || cells.h[c[0]] < h;
+      const c1 = c[1] >= n || cells.h[c[1]] < h;
+      const c2 = c[2] >= n || cells.h[c[2]] < h;
+      const v = vertices.v[current]; // neighboring vertices
+      if (v[0] !== prev && c0 !== c1) current = v[0];
+      else if (v[1] !== prev && c1 !== c2) current = v[1];
+      else if (v[2] !== prev && c0 !== c2) current = v[2];
+      if (current === chain[chain.length - 1]) {
+        ERROR && console.error("Next vertex is not found");
+        break;
+      }
+    }
+    return chain;
+  }
+
+  function simplifyLine(chain, simplification) {
+    if (!simplification) return chain;
+    const n = simplification + 1; // filter each nth element
+    return chain.filter((d, i) => i % n === 0);
+  }
+
+  TIME && console.timeEnd("drawHeightmap");
+}
diff --git a/modules/submap.js b/modules/submap.js
index 5389bcaa..d40e225a 100644
--- a/modules/submap.js
+++ b/modules/submap.js
@@ -208,7 +208,6 @@ window.Submap = (function () {
 
     stage("Regenerating river network.");
     Rivers.generate();
-    drawRivers();
     Lakes.defineGroup();
 
     // biome calculation based on (resampled) grid.cells.temp and prec
diff --git a/modules/ui/heightmap-editor.js b/modules/ui/heightmap-editor.js
index fa1427f3..fa9227eb 100644
--- a/modules/ui/heightmap-editor.js
+++ b/modules/ui/heightmap-editor.js
@@ -237,7 +237,6 @@ function editHeightmap(options) {
       }
     }
 
-    drawRivers();
     Lakes.defineGroup();
     Biomes.define();
     rankCells();
diff --git a/modules/ui/layers.js b/modules/ui/layers.js
index acb8736a..886ba9f0 100644
--- a/modules/ui/layers.js
+++ b/modules/ui/layers.js
@@ -184,9 +184,7 @@ function restoreLayers() {
   if (layerIsOn("toggleZones")) drawZones();
   if (layerIsOn("toggleBorders")) drawBorders();
   if (layerIsOn("toggleStates")) drawStates();
-
-  // some layers are rendered each time, remove them if they are not on
-  if (!layerIsOn("toggleRivers")) rivers.selectAll("*").remove();
+  if (layerIsOn("toggleRivers")) drawRivers();
 }
 
 function toggleHeight(event) {
@@ -204,151 +202,6 @@ function toggleHeight(event) {
   }
 }
 
-function drawHeightmap() {
-  TIME && console.time("drawHeightmap");
-
-  const ocean = terrs.select("#oceanHeights");
-  const land = terrs.select("#landHeights");
-
-  ocean.selectAll("*").remove();
-  land.selectAll("*").remove();
-
-  const paths = new Array(101);
-
-  // ocean cells
-  const renderOceanCells = Boolean(+ocean.attr("data-render"));
-  if (renderOceanCells) {
-    const {cells, vertices} = grid;
-    const used = new Uint8Array(cells.i.length);
-
-    const skip = +ocean.attr("skip") + 1 || 1;
-    const relax = +ocean.attr("relax") || 0;
-    lineGen.curve(d3[ocean.attr("curve") || "curveBasisClosed"]);
-
-    let currentLayer = 0;
-    const heights = Array.from(cells.i).sort((a, b) => cells.h[a] - cells.h[b]);
-
-    for (const i of heights) {
-      const h = cells.h[i];
-      if (h > currentLayer) currentLayer += skip;
-      if (h < currentLayer) continue;
-      if (currentLayer >= 20) break;
-      if (used[i]) continue; // already marked
-      const onborder = cells.c[i].some(n => cells.h[n] < h);
-      if (!onborder) continue;
-      const vertex = cells.v[i].find(v => vertices.c[v].some(i => cells.h[i] < h));
-      const chain = connectVertices(cells, vertices, vertex, h, used);
-      if (chain.length < 3) continue;
-      const points = simplifyLine(chain, relax).map(v => vertices.p[v]);
-      if (!paths[h]) paths[h] = "";
-      paths[h] += round(lineGen(points));
-    }
-  }
-
-  // land cells
-  {
-    const {cells, vertices} = pack;
-    const used = new Uint8Array(cells.i.length);
-
-    const skip = +land.attr("skip") + 1 || 1;
-    const relax = +land.attr("relax") || 0;
-    lineGen.curve(d3[land.attr("curve") || "curveBasisClosed"]);
-
-    let currentLayer = 20;
-    const heights = Array.from(cells.i).sort((a, b) => cells.h[a] - cells.h[b]);
-    for (const i of heights) {
-      const h = cells.h[i];
-      if (h > currentLayer) currentLayer += skip;
-      if (h < currentLayer) continue;
-      if (currentLayer > 100) break; // no layers possible with height > 100
-      if (used[i]) continue; // already marked
-      const onborder = cells.c[i].some(n => cells.h[n] < h);
-      if (!onborder) continue;
-      const vertex = cells.v[i].find(v => vertices.c[v].some(i => cells.h[i] < h));
-      const chain = connectVertices(cells, vertices, vertex, h, used);
-      if (chain.length < 3) continue;
-      const points = simplifyLine(chain, relax).map(v => vertices.p[v]);
-      if (!paths[h]) paths[h] = "";
-      paths[h] += round(lineGen(points));
-    }
-  }
-
-  // render paths
-  for (const height of d3.range(0, 101)) {
-    const group = height < 20 ? ocean : land;
-    const scheme = getColorScheme(group.attr("scheme"));
-
-    if (height === 0 && renderOceanCells) {
-      // draw base ocean layer
-      group
-        .append("rect")
-        .attr("x", 0)
-        .attr("y", 0)
-        .attr("width", graphWidth)
-        .attr("height", graphHeight)
-        .attr("fill", scheme(1));
-    }
-
-    if (height === 20) {
-      // draw base land layer
-      group
-        .append("rect")
-        .attr("x", 0)
-        .attr("y", 0)
-        .attr("width", graphWidth)
-        .attr("height", graphHeight)
-        .attr("fill", scheme(0.8));
-    }
-
-    if (paths[height] && paths[height].length >= 10) {
-      const terracing = group.attr("terracing") / 10 || 0;
-      const color = getColor(height, scheme);
-
-      if (terracing) {
-        group
-          .append("path")
-          .attr("d", paths[height])
-          .attr("transform", "translate(.7,1.4)")
-          .attr("fill", d3.color(color).darker(terracing))
-          .attr("data-height", height);
-      }
-      group.append("path").attr("d", paths[height]).attr("fill", color).attr("data-height", height);
-    }
-  }
-
-  // connect vertices to chain
-  function connectVertices(cells, vertices, start, h, used) {
-    const n = cells.i.length;
-    const chain = []; // vertices chain to form a path
-    for (let i = 0, current = start; i === 0 || (current !== start && i < 20000); i++) {
-      const prev = chain[chain.length - 1]; // previous vertex in chain
-      chain.push(current); // add current vertex to sequence
-      const c = vertices.c[current]; // cells adjacent to vertex
-      c.filter(c => cells.h[c] === h).forEach(c => (used[c] = 1));
-      const c0 = c[0] >= n || cells.h[c[0]] < h;
-      const c1 = c[1] >= n || cells.h[c[1]] < h;
-      const c2 = c[2] >= n || cells.h[c[2]] < h;
-      const v = vertices.v[current]; // neighboring vertices
-      if (v[0] !== prev && c0 !== c1) current = v[0];
-      else if (v[1] !== prev && c1 !== c2) current = v[1];
-      else if (v[2] !== prev && c0 !== c2) current = v[2];
-      if (current === chain[chain.length - 1]) {
-        ERROR && console.error("Next vertex is not found");
-        break;
-      }
-    }
-    return chain;
-  }
-
-  function simplifyLine(chain, simplification) {
-    if (!simplification) return chain;
-    const n = simplification + 1; // filter each nth element
-    return chain.filter((d, i) => i % n === 0);
-  }
-
-  TIME && console.timeEnd("drawHeightmap");
-}
-
 function getColor(value, scheme = getColorScheme("bright")) {
   return scheme(1 - (value < 20 ? value - 5 : value) / 100);
 }
diff --git a/modules/ui/tools.js b/modules/ui/tools.js
index 33bff1aa..91addfaa 100644
--- a/modules/ui/tools.js
+++ b/modules/ui/tools.js
@@ -128,8 +128,7 @@ function regenerateRivers() {
   Rivers.generate();
   Lakes.defineGroup();
   Rivers.specify();
-  if (!layerIsOn("toggleRivers")) toggleRivers();
-  else drawRivers();
+  if (layerIsOn("toggleRivers")) drawRivers();
 }
 
 function recalculatePopulation() {