# Calculating Algae from NDR readings

Hello all,

I am interpreting the final results of the NDR model. Various

literature sources have talked about the relationship nitrogen and phosphorous

has to algae growth. I have been able to find equations that could possibly be

used to get the quantity of algae able to grow based on the exported amounts of

nutrients. The main equation is below. Was wondering if anybody has done this

sort of calculation before and their recommendations.

Ca=Qi*V*Kd(o2)^(T-20)-Ca*V*Kc*1/Z-Qo*Ca+Ca*F6(Tr)/Z*V*Kp*f7(T)*S/Ms+S*IN/Mn+IN*Ip/Mp+Ip

Where Qi: volume of inflow, Kc coefficient for velocity of

settlement, Qo Volume of

outflow, Ca is the total algae concentration in the lake, Kd is the decomposition

reaction, o2 temperature coefficient chl-a, T water temperature, f6(Tr) function

for caluclation of eophotic zone using values for transparency, Kp is the coefficient

for rate of production, f7(T) is the function for effect of temperature on

production of algae, S solar radiation, Ms Michaelis constant for solar

radiation, IN Function for dependence on nutrient salt concentration of

nitrogen, IP Function for dependence on nutrient salt concentration of

phosphorous, Mn Michaelis constant for IN, and Mp Michaelis constant for IP

(JICA, 1980). At the current time I am able to have all the variables and the

equation in an excel spreadsheet. I would like to be able to maintain such a plug-in

workflow with any equation I use.

Thank you for your time,

Thomas Price