CEE 577 |
Spring 2006 |
Problem Statement Use the extended Streeter-Phelps equation (including CBOD deoxygenation, NBOD deoxygenation, and SOD) and model the Ware River from the Ware WWTP discharge (river mile 10.8) to its confluence with the Swift River (river mile 0.8). Consider only the Ware WWTP discharge (2 MGD design flow), although other point and nonpoint sources may exist.
Work in groups of about three, and prepare one report per group. The report should include stream DO predictions and graphical profiles in accordance with the analysis of treatments and requirements of the sensitivity analysis. These profiles should cover the region from the outfall to at least 2 miles downstream of the minimum. Model coefficients and important assumptions must be presented in a clear fashion. A series of recommendations should be made outlining: (1) the necessary level of treatment for the Ware WWTP; and (2) the model coefficients that must be better defined before Ware should be forced to take action.
The design conditions are the 7Q10 flow and 27^{o}C throughout.
Procedure
1. Determination of Stream Geometry for
Streeter-Phelps analysis
a. Establish a number of separate reaches corresponding to differences in stream geometry and kinetic coefficients.
b. Determine the drainage area - flow coefficient for the:
i. 7Q10 conditions (see part c, pg 61),
ii. 1972 time of travel study (see part a, pg 106), and
iii. 1973 time of travel study (see part a, pg 107)
c. Calculate average flows in each of the reaches for the 7Q10 conditions, the day of the 1972 time-of-travel study, and the day of the 1973 time-of-travel study based on the above coefficient and the drainage areas (see part d, pg 56).
d. Determine the velocity-flow coefficients, "c" and "d" (from U=cQ^{d}) for each reach using the time of travel data (part a, pg 106-107) and flows based on drainage areas (part d, pg 56). Then determine 7Q10 velocities for each of the six reaches.
e. Calculate the depth-flow coefficient, "a" (from H=aQ^{b}) and then the average depth under 7Q10 conditions for each reach.
i. Assume the depth exponential coefficient, b=0.3 (i.e., H=aQ^{0.3}).
ii. The following depth data were collected on a day that the flow at the Gibbs Crossing USGS gage was 84 cfs:
River Mile |
Avg Depth (ft) |
26.4-23.3 |
2.5 |
23.3-19.5 |
3.0 |
19.5-16.6 |
1.5 |
16.6-14.5 |
2.0 |
14.5-12.2 |
5.0 |
12.2-11.7 |
2.0 |
11.7-10.8 |
1.5 |
10.8- 8.8 |
1.75 |
8.8- 5.8 |
2.5 |
5.8- 4.4 |
3.0 |
4.4- 3.1 |
8.0 |
3.1- 2.3 |
1.5 |
2.3- 0.8 |
1.5 |
2. Use the Simplified
Analytical Method for Waste Load Allocations
(Although strictly speaking, the USEPA does
not recommend that this method be used with a river as large as the Ware). Considering the number of calculations
required for the sensitivity analysis, the development of a computer program or
use of a computer spreadsheet is highly recommended. (do not forget to
adjust kinetic coefficients to the design temperature)
Additional notes:
i. This
section of the
ii. Assume that the unionized ammonia ambient water quality
standard for a warm water fishery under these conditions is 0.006 mg/L.
iii. Assume the water immediately upstream of the outfall has
the following characteristics:
5
mg/L Ultimate
BOD 0.10
mg/L total ammonia
pH 7.0, 10 mg/L
alkalinity 7.5
mg/L dissolved oxygen
iv. The
Ware WWTP effluent has an alkalinity of 15 mg/L, a pH of 6.8 and a dissolved
oxygen concentration of 7.5 mg/L.
v. Assume
that the sediment oxygen demand is elevated to a distance of 0.3 miles
downstream of the Ware WWTP discharge.
vi. Assume
that this stretch of the
vii. In
your sensitivity analysis, consider temperatures in the range of 25^{o}C
to 30^{o}C.
References (I believe I have enough copies for each group to have their own)
"The
part a, Water Quality Survey
part c, Water Quality Analysis
part d, Water Quality Management Plan
Work in the same groups of 2 or 3 for this project as you did for the first part of the Ware River study. Download the latest version of QUAL2K from the EPA website (http://www.epa.gov/ATHENS/wwqtsc/html/qual2k.html). Install it on the computer you wish to use. Use the Ware River Data and results from your first design project to prepare the following:
1. Use the existing input file and simplify so that the model results can be easily tested against a Streeter-Phelps calculation. This can be significantly simpler that what you did in Part A. I would recommend a uniform channel geometry, flow and only a single point BOD load in the first segment. Compare the QUAL2K results with what you calculate using the Streeter-Phelps equation (e.g., with a spreadsheet).
2. Prepare an input file and run QUAL2K with BOD, DO and Nitrogen modeling. (Note: do not choose "trapezoidal channels". Run the model and graph dissolved oxygen across the entire length of interest. Do these results match those that you obtained in the first part of the Ware River design project? Discuss.
3. Modify input file to include algal, temperature and phosphorous modeling. Use your best estimates for the required parameters. In many cases you may wish to use the default values. (Note: I advise you to use the "daily-temp" light averaging option. I also advise an algal settling velocity of below 0.2 ft/d, and an algal preference factor for ammonia of about 0.5). Run the model and examine the output. Prepare a graph of dissolved oxygen and any other water quality parameters you deem important. Compare the DO plot with that which was produced in #1 of this design project. Discuss.
Prepare a brief report (1 per group) that summarizes what you've done. This should include your general methodology as well as the plots and discussion.
Project Assigned: 4 April 06
Draft Report on Part A1: Due 11 April 06
Draft Report on Part A2: Due 20 April 06
Draft Report on Part B: Due 2 May 06
Final Report (Parts A&B): Due 9 May 06