Finding the position of the lowest value in a Von Neumann Neighborhood

I have a 2 dimensonal array in Javascript with floats inside. I have to iterate over every item in the array and find the position of the lowest float in a Von Neumann Neighborhood. The problem is I know how I find the lowest value, but not how to find the position of this value in the array.

I think there has to be a simple solution for that, but I just can't get my head around it. I think I have a "programmer's block" :D I hope you understand my problem, english is not my first language.

Background I tried implementing a hydraulic erosion algorithm to my terrain generator, which I wrote in JavaScript and WebGL. The algorithm I'm trying to use is the optimized hydraulic erosion algorithm described in "Realtime Procedural Terrain Generation" from Jacob Olsen, 2004

If you know how to know the right, you just to do a double loop

function findStuff(array2D){
  for(var x = 0, max = array2D.length; x < max; x++){// parse each row
    var row = array2D[x];
    for(var y = 0, maxY = row.length; y < maxY; y++){// parse each col
       // do stuff here
       if(anyConditionFilled){
          return [x,y];// will return an array with x at index 0, and y at index 1
       }
    }
  }
}
var res = findStuff(myArray2D);
console.log('res : ', res);