Wetland Problem

Determine the colorform decrease for 2 miles of the Santa Fe river study assuming that the discharge from the treatment plant is 400 count/100 mills and that the discharge make up 5cfs of the total flow down the river. This is the winter flow rate when most of the discharge is coming from the wastewater treatment plan. Determine the concentration in the winter and in the peak  flow on April  15 1992. Use the EPA wetland program to do the calculations.

see

Santa- fe Study 

for the needed information about the river wetlands.

See

http://nwis.waterdata.usgs.gov/nm/nwis/discharge/

to get the stream flow data for the Santa Fe river including the velocity of the river.

 

Is the calculated concentration below the drinking water standard.

Answer. 

Input for wetland 

a. You need to get length width and depth  and flow rate and velocity  for the two flow conditions from the discharge data.

Get flow data for 1992  

Flow  length measured  width ft measured  depth ft measured  velocity f/s measured 
5 cfs= 0.141 cms  2 miles= 10560 ft=  3218 m  11ft = 3.35 m  1.7ft = 0.52 m  0.2 ft/s=0.06 m/s = 6 cm/s
100 cfs=  2.80 cms  2 miles= 10560 ft=  3218 m  15 ft = 4.5 m  3ft = 0.91 m  3ft/s= 0.91 ms/s= 91.4 cm/s

Put data in spread sheet and plot cfs vs width, depth and velocity. see

santa-fe-river.xls 

 

 

Get Temperature average for month of winter and for April. see regional climate center. http://www.wrcc.dri.edu/summary/climsmnm.html

Nov- Feb average tem 32 F in April average Temp is 47 F which is  0 C and 8.3 C 

Put values in prewet. 

answer concentration goes from 400 to 363 count/100 mills  for the low flow

for High flow concentration  the input is diluted

q1*c1+q2*c2= qtotal*c3

q1= 5cfs     c1= 400 colonies counts/100 mills     q2= 95 cfs c2= 0     qtotal= 100 cfs

solve for c3 = 20colonies counts/100 mills

 

Input into model and results are 19.64  with a residence time of 0.05 days  The input file for the model can be down loaded You can then load into the program and run to compare input and out to your solution.

You may get different answer than I did by slight different calculation of width , depth and height  and consequently velocity. Show all results. Capture screens .