Hydrologic Response Units

Units of common soils, land cover, and slope used in continuous simulation modeling.

Description

Hydrologic response units (HRUs) are discretized landscape units based on common soils, land cover, and slope characteristics. The HRU approach provides a computationally efficient method of pre-computing hydrologic response for later use. Results for a particular watershed can be calculated by summing or averaging the results for individual HRUs.

Each combination of parameters was modeled in separate batched simulations. HRUs were designated by a three-digit number according to the following convention:

First digit: Hydrologic Soil Group Number (0 = A/B, 1 = C, 2 = Saturated)
Second digit: Land cover (0=Forest, 1=Pasture, 2=Lawn, 5=Impervious)
Third Digit: Slope (0=Flat, 1=Mod, 2=Steep)

For example, a site with Type C soils, with forested land cover, on a moderate slope would be represented by 101. This schema allowed for HRUs to be stored as an eight-bit unsigned integer on a Puget-Sound wide raster, minimizing storage size.

Layer Access in Earth Engine

The javascript commands below can be used to access this layer within the Google Earth Engine Code Editor. A Google Earth Engine account is required.

// Import the layer data dictionary
var data = require('users/stormwaterheatmap/apps:data/public')

// To view data dictionary, print to the console:
print('Data:', data)

//Get this layer from the layer data dictionary: 
var layer_name = data.rasters["Hydrologic Response Units"]

Viewing

Individual objects contain all the info used in the stormwater heatmap. To add it to the map, add the layer object.

var display_image = layer_name.layer
Map.addLayer(display_image)

Analysis

To get the raw image data for analysis, access the eeObject key.

var raw_image = layer_name.layer.eeObject
Map.addLayer(raw_image,{},'Hydrologic Response Units')

Layer Full-Extent Download

Click the "download" link to initiate the download process. The data will download as a GeoTIFF file (the file size is listed beside the layer name) and a WGS 84 projection. The resolution is the finest available based on the source data.

Hydrologic Response Units (99.4 MB) download

Visualization

Palette

Label	Raster value	Colors
Outwash, Forest, Flat	0	`#e5f5f9`
Outwash, Forest, Moderate	1	`#99d8c9`
Outwash, Forest, Steep	2	`#2ca25f`
Outwash, Pasture, Flat	10	`#e0ecf4`
Outwash, Pasture, Moderate	11	`#9ebcda`
Outwash, Pasture, Steep	12	`#8856a7`
Outwash, Lawn , Flat	20	`#e0f3db`
Outwash, Lawn , Moderate	21	`#a8ddb5`
Outwash, Lawn , Steep	22	`#43a2ca`
Till, Forest, Flat	100	`#ece7f2`
Till, Forest, Moderate	101	`#a6bddb`
Till, Forest, Steep	102	`#2b8cbe`
Till, Pasture, Flat	110	`#ece2f0`
Till, Pasture, Moderate	111	`#a6bddb`
Till, Pasture, Steep	112	`#1c9099`
Till, Lawn , Flat	120	`#e7e1ef`
Till, Lawn , Moderate	121	`#c994c7`
Till, Lawn , Steep	122	`#dd1c77`
Saturated, Forest, Flat	200	`#fde0dd`
Saturated, Forest, Moderate	201	`#fa9fb5`
Saturated, Forest, Steep	202	`#c51b8a`
Saturated, Pasture, Flat	210	`#edf8b1`
Saturated, Pasture, Moderate	211	`#7fcdbb`
Saturated, Pasture, Steep	212	`#2c7fb8`
Saturated, Lawn , Flat	220	`#f7fcb9`
Saturated, Lawn , Moderate	221	`#addd8e`
Saturated, Lawn , Steep	222	`#31a354`
Impervious, Flat	250	`#fee6ce`
Impervious, Moderate	251	`#fdae6b`
Impervious, Steep	252	`#e6550d`