Dissolved Oxygen. Xxxxxx/Xxxxx/Croton Project – No less than 5 mg/L in the project tail-waters.
Dissolved Oxygen. The results of these parameters will be reported after each sampling event and on the final report along with the results of the analyses performed in the laboratory. The field meters shall be calibrated on a daily basis. A field log will be kept each day that samples are collected. The field log will include: • Name and signature of the person collecting the samples • Location and sampling site • Weather information • Dates and times of sample collection • Field measurements • Descriptions of any unusual conditions at the sample locations • Chains of Custody • Indication of duplicate sample location All samples will be placed in appropriate containers provided by NSWRD. All containers will be properly labeled. The duplicate sample will be labeled with the sample location and identified as “duplicate”. When preservation is required, pre-preserved bottles will be used. Samples will be placed inside a cooler with wet ice until they reach the laboratory.
Dissolved Oxygen. In the connecting channels and in the upper waters of the Lakes, the dissolved oxygen level should not be less than 6.0 milligrams per liter at any time; in hypolimnetic waters, it should not be less than necessary for the support of fish life, particularly cold water species.
Dissolved Oxygen. The analysis will also look at methods of increasing waterway-dissolved oxygen, which falls below existing and proposed standards, especially after storm events. Water quality modeling is included in the analysis. The Illinois EPA and U.S. EPA are jointly reviewing the permit required Combined Sewer Overflow (CSO) public notification plans for both MWRDGC and the City of Chicago. Following the completion of that review, Illinois EPA & U.S. EPA will submit comments to MWRDGC. MWRDGC will then revise and resubmit their CSO public notification plan, including CSO outfall sign language. Illinois EPA will review the revised MWRDGC CSO public notification plan details, and if the permittee=s (MWRDGC) proposed plan is acceptable to Illinois EPA, Illinois EPA will send an approval letter to MWRDGC. Illinois EPA=s approval letter, per MWRDGC permit language, triggers a three-month timeframe within which MWRDGC must implement the plan, including posting of signs. Illinois EPA and U.S. EPA will cooperatively pursue timely completion and implementation of a CSO public notification plan by the City of Chicago similar to and compatible with the plan being developed and implemented by the District. Direct communication among the City, Agency and region will be initiated during November 2004 with the intent that public notification practices be functional. Illinois EPA and U.S. EPA will consider all available options to achieve this objective including administrative and, if appropriate, enforcement approaches.
Dissolved Oxygen. Dissolved Oxygen values for Tanyard Creek and Stone Mountain Creek showed a normal distribution of DO while Peavine Creek showed a skewed right distribution of DO for the sampling season (Appendix A: Figure 9, Figure 14, Figure 19). The distribution of DO readings for Peavine indicates that more values were higher than lower and the higher values had a greater influence on the overall average. This difference in DO can be attributed to the physical habitat of the stream site sampled as well as the difference in volume and velocity of the water flowing in the water body. The Wilcoxon Rank Sum Test results for DO indicate that a statistically significant difference between median rank value for DO existed between Peavine Creek and Stone Mountain Creek (p<0.0003) and between Tanyard Creek and Peavine Creek (p<0.0086), but not between Tanyard Creek and Stone Mountain Creek (p>0.1423). Taking into consideration that DO is dependent upon temperature (colder water can hold more oxygen than warmer water) and physical characteristics of the creek, this is a plausible observation because sampling was done at different times of the day for each creek and the adjacent land use of each creek differs from each other. Sampling at Tanyard Creek was done in the early morning between 8AM and 11AM, and the adjacent land use of the creek includes an increase in impervious surfaces near parks and residential areas and a golf course. Runoff from the impervious surfaces and from the golf course can cause an increase in chemical pollutants, and in addition Tanyard Creek is a CSO overflow facility which is victim to a decrease in nutrient content and an increase in salt and runoff into the water. Peavine Creek was sampled in the mid afternoon from 12PM to 2PM, and changes in the land use from site PA to site PD could be a possible cause for the fluctuations in DO throughout the stream. Stone Mountain Creek was sampled in the late afternoon between 3PM and 6PM and had the lowest average DO levels among the creeks: mean DO at Stone Mountain Creek was 8.491 mg/L, 8.902 mg/L at Tanyard Creek, and 9.494 mg/L at Peavine Creek. The lower average DO level at Stone Mountain is surprising because there is not runoff from impervious surfaces or from human interaction with the water. In addition because the creek is nestled away in the xxxxx it is protected from the affects of development. Dissolved Oxygen is an important indicator of how polluted the water is and how well the water can suppo...
Dissolved Oxygen. The water quality standards for DO state that concentrations “shall have a one-day minimum 8.0 milligrams per liter (mg/L)”. All measurements taken in the Reservoir complied with that standard (Figure 2-2). Increasing DO concentrations were measured from upriver to downriver each month. The lowest DO measured in water year (WY) 2000 was 8.26 mg/L in September at the Xxxxx Dam tailrace. Average DO concentrations were commonly over 10 mg/L for all categories of stations. The DO levels increased as water moved downstream through the Reservoir and the same increasing trend was observed, for all months except May, when comparing DO at the Rocky Reach Dam tailrace to the Xxxxx Dam tailrace. These differences averaged 0.35 mg/L for all months, with largest differences in October, February, and May. Generally, littoral DO concentrations were greater than at pelagic stations, but the average differences were less than 0.15 mg/L. One-meter DO monthly profiles show little variability among categories (littoral, pelagic or tailrace) of stations.
Dissolved Oxygen. To avoid nuisance conditions, dissolved oxygen shall be maintained at not less than 2.0 mg/ l as a daily average and at no time allowed to fall to anoxic levels.
Dissolved Oxygen. Due to large fluctuations in influent AMD dissolved oxygen (DO) values through time; these values were used as a baseline for comparison of DO measurements made for each reactor. Therefore, Figures 15 & 16 outline the changes in dissolved oxygen (ΔDO) from influent to the simulated acid impoundments (AMD overlying the treatment media within the barrels) and then simulated acid impoundments to effluent, respectively. The following equations were used to derive values obtained for each figure: DO(Acid Impoundment) - DO(Influent) = ΔDO(In 🡪 AI) (Figure 15) DO(Effluent) - DO(Acid Impoundment) = ΔDO(AI 🡪 Eff) (Figure 16) Where DO(Influent), DO(Acid Impoundment) and DO(Effluent) represents the absolute dissolved oxygen values in ppm measured at the AMD influent, the reactor’s acid impoundment and the reactor’s effluent, respectively. Thus, positive ΔDO values represent net increases in DO concentration and negative ΔDO values coincide with net consumption of DO as AMD influent travels to the acid impoundments and then though the treatment media to exit the effluent ports of each reactor. Overall R1 through R6 displayed the same values in ΔDO(In🡪AI) and ΔDO(AI🡪Eff) values throughout the entire experiment. During the first two months (August-October 2012) there was an average decrease in DO (ΔDO(In🡪AI) = -2.71 ppm) measurements from the influent to the acid impoundment of each reactor. The following five months (November 2012-March 2013) displayed an average increase in DO (ΔDO(In🡪AI) = +3.77ppm) from the influent to the acid impoundments on top of each reactor. ΔDO (ppm) Figure 15: Changes in dissolved oxygen measurements (DO) from influent AMD to the acid impoundments of each reactor (R1-R6). Positive ΔDO correspond to a net increase in DO from influent while negative ΔDO indicates a net decrease. As for the final months of the experiment (May 2013 – early September 2013) an overall decrease of DO (ΔDO(In🡪AI) = -1.11ppm) was once again measured. In contrast, during the first two months (August – October 2012) a slight increase in DO (ΔDO(AI🡪Eff) = +0.24ppm) was measured on average from the acid impoundments to the effluent ports of each reactor. A striking decrease in DO (ΔDO(AI🡪Eff) = -7.63ppm) was recorded in the following five months (November 2012-March 2013). Finally, an overall increase in DO (ΔDO(AI🡪Eff) = +0.87ppm) was measured from the acid impoundment to the effluent port of each reactor in the last experimental months (May 2013 ...
Dissolved Oxygen. 020201 ................ Bayou Des Allemands—Lac Des Allemands to Hwy. U.S. 90 (scenic) ................................................ Nutrients.
Dissolved Oxygen. 020303 ................ Lake Cataouatche and Tributaries .........................................................................................................
