a) Criteria should be as detailed and objective as possible. So, the 'extent' of something is rather vague and should be avoided. The other three are objective quantitative measures and are preferred. However, the average subsidence, does not give information related to the decline of nature. A large subsidence taking place locally and a small subsidence taking place globally, can have completely different results. Thus, this criterion is also disregarded.

b) Other criteria might be:

• the chance of extinction of rare species due to flooding of their breeding grounds
• the area affected by subsidence, as a percentage of the total
• the speed of subsidence related to the 'elasticity' of nature (how fast can nature restore the subsidence by import of sediment)
• the size of the project benefits for the government, relative to other incomes.