diff --git a/Effects/model-combined.eff b/Effects/model-combined.eff
index d42c052ca..25da2b7cf 100644
--- a/Effects/model-combined.eff
+++ b/Effects/model-combined.eff
@@ -98,6 +98,8 @@ please see Docs/README.model-combined.eff for documentation
 			<internal-format>normalized</internal-format>
 		</texture>
 		<!-- END Grain texture -->
+		<!-- simulate rain effects -->
+		<rain-enabled type="int">0</rain-enabled>
 		<!-- 		Dirt -->
 		<dirt-enabled type="int">0</dirt-enabled>
 		<dirt-multi type="int">0</dirt-multi>
@@ -133,6 +135,8 @@ please see Docs/README.model-combined.eff for documentation
 		<scattering><use>/rendering/scene/scattering</use></scattering>
 		<terminator><use>/environment/terminator-relative-position-m</use></terminator>
 		<fogtype><use>/sim/rendering/shaders/skydome</use></fogtype>
+    		<wetness><use>/environment/surface/wetness</use></wetness>
+		<rnorm><use>/environment/rain-norm</use></rnorm>
 		<cloudpos1_x><use>/local-weather/cloud-shadows/cloudpos-x[0]</use></cloudpos1_x>
 		<cloudpos1_y><use>/local-weather/cloud-shadows/cloudpos-y[0]</use></cloudpos1_y>
 		<cloudpos2_x><use>/local-weather/cloud-shadows/cloudpos-x[1]</use></cloudpos2_x>
@@ -427,6 +431,7 @@ please see Docs/README.model-combined.eff for documentation
 				<fragment-shader n="2">Shaders/cloud-shadowfunc.frag</fragment-shader>
 				<fragment-shader n="3">Shaders/hazes.frag</fragment-shader>
 				<fragment-shader n="4">Shaders/secondary_lights.frag</fragment-shader>
+				<fragment-shader n="5">Shaders/noise.frag</fragment-shader>
 			   </program>
 			   
 			   <uniform>
@@ -730,6 +735,15 @@ please see Docs/README.model-combined.eff for documentation
 				   </value>
 		  	   </uniform>
 
+			   <!-- simulate wetness and rain-->
+		  	   <uniform>
+				   <name>rain_enabled</name>
+				   <type>int</type>
+				   <value>
+			  	   	<use>rain-enabled</use>
+				   </value>
+		  	   </uniform>
+
 			   <!-- set the amount of ambient light correction 0.0 - 1.0  -->
 			   <uniform>
 				   <name>amb_correction</name>
@@ -849,6 +863,16 @@ please see Docs/README.model-combined.eff for documentation
        				   <type>float</type>
        				   <value><use>air_pollution</use></value>
      			   </uniform>
+   			   <uniform>
+        			   <name>rain_norm</name>
+       				   <type>float</type>
+       				   <value><use>rnorm</use></value>
+     			   </uniform>
+   			   <uniform>
+        			   <name>wetness</name>
+       				   <type>float</type>
+       				   <value><use>wetness</use></value>
+     			   </uniform>
 			   <uniform>
          			   <name>view_pitch_offset</name>
     				   <type>float</type>
diff --git a/Shaders/model-ALS-ultra.frag b/Shaders/model-ALS-ultra.frag
index de77008ce..291018d46 100644
--- a/Shaders/model-ALS-ultra.frag
+++ b/Shaders/model-ALS-ultra.frag
@@ -35,6 +35,7 @@ uniform int nmap_enabled;
 uniform int refl_enabled;
 uniform int refl_map;
 uniform int grain_texture_enabled;
+uniform int rain_enabled;
 uniform int cloud_shadow_flag;
 uniform int use_searchlight;
 uniform int use_landing_light;
@@ -54,6 +55,8 @@ uniform float refl_fresnel;
 uniform float refl_noise;
 uniform float refl_rainbow;
 uniform float grain_magnification;
+uniform float wetness;
+uniform float rain_norm;
 
 uniform float avisibility;
 uniform float cloud_self_shading;
@@ -68,6 +71,8 @@ uniform float terrain_alt;
 uniform float visibility;
 uniform float air_pollution;
 
+uniform float osg_SimulationTime;
+
 uniform float landing_light1_offset;
 uniform float landing_light2_offset;
 
@@ -85,6 +90,7 @@ uniform vec3 dirt_r_color;
 uniform vec3 dirt_g_color;
 uniform vec3 dirt_b_color;
 
+float DotNoise2D(in vec2 coord, in float wavelength, in float fractionalMaxDotSize, in float dot_density);
 float shadow_func (in float x, in float y, in float noise, in float dist);
 float fog_func (in float targ, in float altitude);
 float rayleigh_in_func(in float dist, in float air_pollution, in float avisibility, in float eye_alt, in float vertex_alt);
@@ -208,11 +214,17 @@ void main (void)
     /// END light
 
     /// BEGIN grain overlay
-    if (grain_texture_enabled > 0)
+    if (grain_texture_enabled ==1)
         {
         grainTexel = texture2D(GrainTex, gl_TexCoord[0].st * grain_magnification);
         texel.rgb = mix(texel.rgb, grainTexel.rgb,  grainTexel.a );
         }
+   else if (grain_texture_enabled == 2)
+	{
+        grainTexel = texture2D(GrainTex, rawpos.xy * grain_magnification);
+        texel.rgb = mix(texel.rgb, grainTexel.rgb,  grainTexel.a );
+	}
+
     /// END grain overlay
 
     ///BEGIN bump
@@ -344,6 +356,31 @@ void main (void)
     //END Dirt
     //////////////////////////////////////////////////////////////////////
 
+    //////////////////////////////////////////////////////////////////////
+    //begin WETNESS
+    //////////////////////////////////////////////////////////////////////
+
+    if (rain_enabled >0.0)
+	{
+    	texel.rgb = texel.rgb * (1.0 - 0.6 * wetness);
+    	float rain_factor = 0.0;
+    	if (rain_norm > 0.0)
+		{
+    		rain_factor += DotNoise2D(rawpos.xy, 0.2 ,0.5, rain_norm) * abs(sin(6.0*osg_SimulationTime));
+    		rain_factor += DotNoise2D(rawpos.xy, 0.3 ,0.4, rain_norm) * abs(sin(6.0*osg_SimulationTime + 2.094));
+    		rain_factor += DotNoise2D(rawpos.xy, 0.4 ,0.3, rain_norm)* abs(sin(6.0*osg_SimulationTime + 4.188));
+		}
+
+    	// secondary reflection of sky irradiance in water film
+    	float fresnelW =  ((0.8 * wetness) ) *  (1.0-smoothstep(0.0,0.4, dot(N,-normalize(vertVec)) * 1.0 - 0.2 * rain_factor * wetness));
+    	float sky_factor = (1.0-ct*ct);
+    	vec3 sky_light = vec3 (1.0,1.0,1.0) * length(light_diffuse.rgb) * (1.0-effective_scattering);
+    	Specular.rgb += sky_factor * fresnelW  * sky_light;
+	}
+    /////////////////////////////////////////////////////////////////////
+    //end WETNESS
+    //////////////////////////////////////////////////////////////////////
+
 
     // set ambient adjustment to remove bluiness with user input
     float ambient_offset = clamp(amb_correction, -1.0, 1.0);