The environmental analysis is not my field directly, but in many countries before whatever aquaculture project may start the farm activities needs to present and environmental and footprint analysis. In a lotic system such as rivers is necessary to incorporate within the analytical model the flow (speed and volumen), the material incorporated to the rivers (fish food: composition of the food, density of the food, porcentaje of food sink to the river's bottom at different distance since the cages, etc). It also necessary incorporate the human activities: operative farm work, antropogenic activities around and linked to the farm, risk to spills, etc. Furthermore, the risk of animals that running away from the cages, the rate of inflow of nutrient to the system, etc, etc But, how is a lotic system, everything needs to be correlated to the plume from the cage, that mean the bathymetric model of the effects (horizontal and vertical).

I expect this could be a help. How I told you it is not directly my field

Water footprint is a term I'm not familiar with (It allures to how much water is consumed by the cage operation). But if it is pollution you are looking for you can calculate the impact in terms of feed inputs as it generates TAN and other waste (it has been calculated for 95% of sp cultivated). The ecological impact in terms of currents, water dynamics, population succession of algae and emergent plants, etc; is a different endeavor and will be part of the environmental Impact statement that many projects are required to do for permitting.

All can be translated to carbon footprint but that is a different set of calculations.

In attachment a probably first approach

Thanks all for helping me out. I am totally new to this idea and not familiar as well. Not my field but have to explore and do some literature. Thank you again..

You can find information for your work in the following web page:

www.waterfootprint.org

they have a new manual available for that matter

Alright. Thank you so much.

The water footprint of an activity is defined as the total volume of freshwater used to actualize a production process and it is measured in water volume consumed (evaporated) and/or polluted per unit of time.

Thus for aquaculture in a flowing river it will be almost an impossible task, unless a volume of water per time is being channeled into an enclosure or pond and re-channeled back to the river, and the water quality of the water is assessed or evaluated before a discharge and a refilling of the enclosure system.

I'm not familiar with the concept, but here a paper you might found interesting.

1994 Soley et al. An Economic Approach to Pollution Control in Aquaculture. Mar. Pol. Bull. 28(3): 170–177. http://bit.ly/10ZRfVb