Update README.md

Author: gassc

README.md

@@ -2,8 +2,35 @@
 
 A map-based application for estimating the power potential of microhydropower installations.
 
+![](https://raw.githubusercontent.com/civicmapper/bard-hydropower/master/docs/bardhydropower_01.jpg)
 
-Built as a demonstration project in collaboration with [Bard College](http://www.bard.edu/) and [Current Hydro](http://www.currenthydro.com/).
+This was built as a demonstration project for [Bard College](http://www.bard.edu/) and [Current Hydro LLC](http://www.currenthydro.com/). The project was funded by [NYSERDA](https://www.nyserda.ny.gov/).
+
+## What It Does
+
+The Microhydropower Calculator helps estimate the power generation potential of a micro-hydroelectric turbine installation. It guides you through these steps:
+
+### 1. Identify a location for microhydropower, and get information about the terrain 
+
+Use the map and available data layers to identify a spot suitable for a potential microhydropower installation. Dam locations (New York State only) and national hydrographic data from US Geological Survey (USGS) are available as map layers. Switch the basemap between several available imagery and topographic styles from Esri and Mapbox to get a better sense of the terrain.
+
+Once you've found a stream or weir, you diagram the location of the installation on the map with the draw tool. The calculator will automatically estimate head (elevation change) and delineate the contributing area using available topographic data. 
+
+The underlying elevation data driving the calculations is provided by the USGS through web services hosted by [ESRI](https://www.esri.com/en-us/home). Where available in New York state, head calculations will rely first on high resolution elevation data services hosted by the [NY State GIS Program Office](http://gis.ny.gov/elevation/DEM-web-services.htm), and fall back to coarser USGS elevation data if needed.
+
+### 2. Set calculation parameters
+
+You can input calculation coefficients and other assumptions used in the calculation (sensible defaults are provided). 
+
+Optionally, you can also override the head and area estimates derived from map in Step 1.
+
+### 3. See the power potential of a microhydropower installation
+
+View the analysis results, including total kilowatt hours and estimated revenue generation.
+
+## More information
+
+The calculator logic is described in the calculator's About section; you can see that same documentation [here](https://github.com/civicmapper/bard-hydropower/blob/master/app/templates/pages/help_methods.md).
 
 ## Architecture Overview
 
@@ -23,21 +50,21 @@ Front-end business logic is written in javascript with only jQuery. Javascript a
 
 ### Configuration (`config.py`)
 
-The application requires a few global configuration variables to be set, mainly to enable access to 3rd-party services.
-
-See `app/config.py` for more information.
-
-_to be completed._
+The application requires a few global configuration variables to be set, mainly to enable access to 3rd-party Esri and Mapbox services. Required services include:
 
 #### ArcGIS Application Registration
 
 * Esri Application ID
 * Esri Application Secret
 
+Get these by registering an application at https://developers.arcgis.com
+
 #### Mapbox Token
 
 * Token
 
+Get this by generating a token from https://www.mapbox.com
+
 ### Development Quickstart
 
 _(for editing HTML and Python only)._