Diurnal Dissolved Oxygen Concentrations

Transcription

1 Diurnal Dissolved Oxygen Concentrations Presented by Marzooq Alebus Division of Watershed Management New Jersey Department of Environmental Protection December 12, 2

2 Outline of Presentation Uses of diurnal dissolved oxygen data in water quality assessment Factors affecting instream concentration of dissolved oxygen Assessment of diurnal dissolved oxygen data Sampling requirements for Total Maximum Daily Loads (TMDLs)

3 Diurnal Dissolved Oxygen (DO) Data Use in Water Quality Assessment Best measurement to assess compliance with SWQS for DO concentration minimum DO concentrations do not usually occur between the hrs of 9AM and 12PM! Use as a response indicator of eutrophication - assessment of use impairment due to nutrient overenrichment Diurnal DO profile can be used to predict stream primary production rate, respiration and stream reaeration rates

4 Factors Affecting Instream Concentrations of DO Reaeration from the atmosphere Solubility of DO in water depends on: Temperature (higher temperature reduces solubility) Partial Pressure (decreasing pressure reduces solubility) Salinity (high salinity reduces solubility) Internal mixing and turbulence, velocity, flow, water depth Stream Biota Photosynthesis Respiration of aquatic plants & organisms

5 Factors Affecting Instream Concentrations of DO Drainage accrual- groundwater inflow, tributaries, point sources, runoffs (could be oxygen rich or poor) Amount of nutrients, organics, dissolved or suspended solids Oxidation of carbonaceous waste material (CBOD) Oxidation of nitrogenous water material (NBOD) Sediment Oxygen Demand (SOD)

6 Dissloved oxygen concentration (mg/l) 1 Seasonal fluctuation of Dissolved Oxygen Concentrations Daily (Mean, Max and Min) USGS 1395 Passaic River below Pompton River at Two Bridges Middle Intake - 1/27-1/ Daily Mean DO Daily Max DO Daily Min DO 1/1/27 11/2/27 1/9/2 2/2/2 /1/2 /7/2 7/27/2 9/15/2

7 DO conc. (mg/l) Flow (cfs) Diurnal DO influenced by rainfall event Raritan River at Manville /2/2 : /7/2 : /12/2 : /17/2 : /22/2 : /27/2 : 7/2/2 : Time

8 Dissolved Oxygen Conc. (mg/l) / ph Flow (cfs) Diurnal DO influenced by high flow event South Branch Raritan River on Studdiford Dr ph DO flow. July 22, 2 July 27, 2 August 1, 2 August, 2 August 11, 2

9 DO conc. (mg/l) DO % Sat. Typical Diurnal DO profile with moderate primary productivity Diurnal Dissolved Oxygen Musconetcong River USGS # Light rain DO DO Sat% Tim e(hrs)

10 Dissolved Oxygen conc. (mg/l) Dissolved oxygen % Sat. Diurnal DO influenced by rainfall event 1 Raritan River at Manville August 2 thru September, RAIN DO ph DO % sat. Temp

11 Dissolved Oxygen conc. (mg/l) Specific Conductance us/cm 12 Diurnal DO profile influenced by a sudden discharge of? WB RAHWAY RIV AT NORTHFIELD AVE AT WEST ORANGE USGS # DO (mg/l) S.C Time (hrs) NO RAIN OCCURRED DURING DATASONDE DEPLOYMENT

12 Diurnal DO for the Assessment of Use Impairment due to Nutrient Overenrichment ( Phosphorus Evaluation Study- exit ramp) Diurnal DO indicates that phosphorus is rendering the water unsuitable for aquatic life use if there are dissolved oxygen fluctuations of 3mg/l or more (indicative of photosynthetic activity) in a 2 hour period, and one of the following events occur at any time during the course of the study: 1) The minimum DO criteria is violated greater than 1% of the time based on continuous monitoring during any 2 hour sampling period; or 2) The DO daily average violates the applicable 2-hour criteria. (FW2-NT : 2 hour average not less than 5., but not less than. at any time. Following examples are FW2-NT

13 Dissolved Oxygen (mg/l) Diurnal DO profile influenced by Sediment Oxygen Demand (SOD) and low primary productivity violation to the 2-hour (5mg/L) DO criterion Dissolved Oxygen % Sat. 1 Millstone River USGS #12 7/31/21 thru /3/ DO (mg/l) DO % Sat Time (hrs)

14 Dissolved Oxygen Conc. (mg/l) DO % Sat. Diurnal DO profile influenced by Sediment Oxygen Demand (SOD) and low primary productivity - No violation to DO criterion Diurnal D.O. Crosswick Ck USGS # DO (mg/l) DO % Sat Time (hrs)

15 Dissolved Oxygen (mg/l) / ph DO % Sat. Diurnal DO profile influenced by excessive productivity ph violations but no dissolved oxygen violations! Neshanic River USGS # 139, July 1-17, DO ph DO %Sat Time (hrs)

16 DO Conc. (mg/l) Diurnal DO profile influenced by excessive productivity - Violation to the minimum DO criterion of mg/l ph (su) 1 1 Diurnal Dissolved Oxygen Concentrations Saddle River at Lodi July 1-19, 22 DO PH Time (hour)

17 Dissolved oxygen Diurnal dissolved oxygen data is proof to be one of the most important parameters in evaluating nutrient impairments when sampled at the right time!

18 Sampling Requirements for D.O. D.O. measurements to be conducted under stable low flow That low flow frequency which is exceeded 7% of the time and occurring a minimum of 72 hours (3 days) after a rainfall event. (a rainfall event is defined as ½ inch or more within any 2 hour period) All Sampling to be done May through September

19 Thank you