Diffuse water pollution estimator

START
prototype green offset tool

Estimate changes in water pollution loads resulting from new developments

This prototype green offset tool estimates the change in pollution loads likely to occur from a specified development type and size. It focuses on land-use change and is recommended for developments up to 5 hecatres in size and as a first-cut estimator for larger developments.

1. Users (including potential developers and consent authorities) input data on:

• existing landuse and site characteristics
• future landuse and site characteristics
• proposed measures to minimise diffuse water pollution.

2. The estimator provides:

• estimates of pre-development pollution loads
• estimates of post-development pollution loads incorporating benefits of the proposed pollution reduction methods
• any increase in net pollution loads. (This is the amount of pollution that would require an offset if the development was located in an area where an offset scheme was operating.)

3. Users can enter alternate pollution reduction measures to evaluate strategies to reduce net pollution loads. 

Pollution load estimates for the following pollutants are currently provided:

• total nitrogen
• total phosphorus