Simple Water Alpha

Would somebody mind making the Simple Water Script's Horizon Color alpha change the water's alpha? Currently, it makes the water just opaque and I want to be able to see through it a little bit. Thanks to anybody who's willing to help, and here's the script:

 Shader "FX/Water (simple)" {
 Properties {
     _horizonColor ("Horizon color", COLOR)  = ( .172 , .463 , .435 , 0)
     _WaveScale ("Wave scale", Range (0.02,0.15)) = .07
     _ColorControl ("Reflective color (RGB) fresnel (A) ", 2D) = "" { }
     _ColorControlCube ("Reflective color cube (RGB) fresnel (A) ", Cube) = "" { TexGen CubeReflect }
     _BumpMap ("Waves Normalmap ", 2D) = "" { }
     WaveSpeed ("Wave speed (map1 x,y; map2 x,y)", Vector) = (19,9,-16,-7)
     _MainTex ("Fallback texture", 2D) = "" { }
 }
 
 CGINCLUDE
 // -----------------------------------------------------------
 // This section is included in all program sections below
 
 #include "UnityCG.cginc"
 
 uniform float4 _horizonColor;
 
 uniform float4 WaveSpeed;
 uniform float _WaveScale;
 uniform float4 _WaveOffset;
 
 struct appdata {
     float4 vertex : POSITION;
     float3 normal : NORMAL;
 };
 
 struct v2f {
     float4 pos : SV_POSITION;
     float2 bumpuv[2] : TEXCOORD0;
     float3 viewDir : TEXCOORD2;
 };
 
 v2f vert(appdata v)
 {
     v2f o;
     float4 s;
 
     o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
 
     // scroll bump waves
     float4 temp;
     temp.xyzw = v.vertex.xzxz * _WaveScale / unity_Scale.w + _WaveOffset;
     o.bumpuv[0] = temp.xy * float2(.4, .45);
     o.bumpuv[1] = temp.wz;
 
     // object space view direction
     o.viewDir.xzy = normalize( ObjSpaceViewDir(v.vertex) );
 
     return o;
 }
 
 ENDCG
     
 // -----------------------------------------------------------
 // Fragment program
 
 Subshader {
     Tags { "RenderType"="Opaque" }
     Pass {
 
 CGPROGRAM
 #pragma vertex vert
 #pragma fragment frag
 #pragma fragmentoption ARB_precision_hint_fastest 
 
 sampler2D _BumpMap;
 sampler2D _ColorControl;
 
 half4 frag( v2f i ) : COLOR
 {
     half3 bump1 = UnpackNormal(tex2D( _BumpMap, i.bumpuv[0] )).rgb;
     half3 bump2 = UnpackNormal(tex2D( _BumpMap, i.bumpuv[1] )).rgb;
     half3 bump = (bump1 + bump2) * 0.5;
     
     half fresnel = dot( i.viewDir, bump );
     half4 water = tex2D( _ColorControl, float2(fresnel,fresnel) );
     
     half4 col;
     col.rgb = lerp( water.rgb, _horizonColor.rgb, water.a );
     col.a = _horizonColor.a;
     return col;
 }
 ENDCG
     }
 }
 
 // -----------------------------------------------------------
 //  Old cards
 
 // three texture, cubemaps
 Subshader {
     Tags { "RenderType"="Opaque" }
     Pass {
         Color (0.5,0.5,0.5,0.5)
         SetTexture [_MainTex] {
             Matrix [_WaveMatrix]
             combine texture * primary
         }
         SetTexture [_MainTex] {
             Matrix [_WaveMatrix2]
             combine texture * primary + previous
         }
         SetTexture [_ColorControlCube] {
             combine texture +- previous, primary
             Matrix [_Reflection]
         }
     }
 }
 
 // dual texture, cubemaps
 Subshader {
     Tags { "RenderType"="Opaque" }
     Pass {
         Color (0.5,0.5,0.5,0.5)
         SetTexture [_MainTex] {
             Matrix [_WaveMatrix]
             combine texture
         }
         SetTexture [_ColorControlCube] {
             combine texture +- previous, primary
             Matrix [_Reflection]
         }
     }
 }
 
 // single texture
 Subshader {
     Tags { "RenderType"="Opaque" }
     Pass {
         Color (0.5,0.5,0.5,0)
         SetTexture [_MainTex] {
             Matrix [_WaveMatrix]
             combine texture, primary
         }
     }
 }
 
 }