Wetland project charts

Wetland Project 2002 Preliminary Results

Since the beginning of the RSBOJC Wetlands TMDL Pilot Project in 2000, the amount of vegetative and biological material has increased substantially. This has resulted in greater surface area available for filtering water.

Analysis of 2002 data, although limited (and biased towards end of irrigation season data), reveals a notable, overall positive change in water quality when tracked from untreated water at the inflow to treated water at the outflows.

Of particular concern are the effects of the wetland on nutrients (e.g. nitrite + nitrate), on indicators of water health (e.g. dissolved oxygen content), and on the total maximum daily load (TMDL) compliance goals set by the Dept. of Ecology (e.g. turbidity). The graphs below illustrate the effect of the wetland’s north & south cells on water quality. Water enters the wetlands at Site 2 (Joint Drain 26.6), proceeds into a sediment basin and is then diverted to the north or south cells before re-entering Joint Drain 26.6. Map of Wetlands.

Total Nitrite + Nitrate Concentration graph

The above graph demonstrates the successful uptake of the excess nutrient NO2+3, which decreases as a result of detention in the wetland cells.

Dissolved Oxygen Concentration graph

The above graph shows that the amount of dissolved oxygen (DO), an important indicator of water health, decreased from inflow to outflow, particularly as a result of detention in the north cell.

Wetlands Turbidity graph

The above graph illustrates how the wetland can contribute to meeting state TMDL goals. Although turbidity is already in compliance in this particular drain prior to entering the wetland, further clarity of water is achieved through detention in the wetland.

Conclusion

Although these results are positive, they are considered preliminary because of the lack of observations. A full season of water monitoring data is required to accurately assess the relative success of the RSBOJC project.

Return to Conservation & Water Quality Wetlands page.

Click here to learn more about settling basins and other water quality methods.

Click here to learn how SVID irrigators have enhanced water conservation.

Click here for more information about the RSBOJC Water Quality Policy

Recent Drain Study Reports

Click here to read the RSBOJC Fish Survey Report.

Click here to read the RSBOJC Drain Habitat Report (pages 1-48)

Click here to read the RSBOJC Drain Habitat Report Appendix (data)

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