In response to your article “Hadid’s aquatics centre fails environment test” (1 December) the updated concept proposals we presented at last week’s media launch are an early step in the process of developing a design for the aquatics centre. However, the environmental and sustainability audit you refer to relates to earlier aquatics centre designs and not the updated concept designs we have just announced.

In developing the concept design, our emphasis has been on the evolution of the design to mitigate energy use by reducing volume and scale. This will have significant benefits for future building energy use, running costs and financial sustainability.

The Olympic Delivery Authority (ODA) aims to create the best possible long-term legacy for all our venues and the outline design proposals are being developed to minimise adverse economic, social or environmental impacts throughout the design and construction. The continuing design development will occur within a framework of BREEAM assessment categories and will be reviewed against these at regular intervals.

Alison Nimmo, ODA director of design and regeneration, and Zaha Hadid, architect