To use treated wood appropriately, you need to fully understand your treatment options and how to select and specify material for different uses. Note that model results will be different for each preservative.
The default selection is for "Washington State Benchmarks" for water and sediment in freshwater and marine environments. However, these may be adjusted to suit your region by selecting "Custom Benchmarks".
Enter the preservative retention in the piling provided by the producer.
Enter the number of piling in rows that most closely parallel the current vector.
Enter the number of rows of pilings.
Enter the average radius of the piling used in the project. For most projects, the value for this input will be between 2 and 11.8 in.
Enter the average distance between the centers of pilings driven in rows paralleling the currents.
This requires access to the project plans. Sum the surface areas of all sawn lumber (all wood excepting piling) that is immersed when the tide is less than or equal to MHW.
When available, enter the average measured retention provided by the treated wood producer. When that information is not available, enter the retention specified for this use in the latest version of the American Wood Protection Standards.
Enter the surface area (cm^2) of all piling and lumber in the structure that is above MHW and exposed to rainfall. For piling the surface area is that area located on all perimeters of the structure. For each perimeter piling, this is pi*r*height above MHW because only the outer half of the piling is exposed to rain. The inner half is assumed to be under the structure. This is provided only as a guide and special circumstances, such as the use of pin piling will require other approaches.
This is generally the same as the Immersed Lumber Retention.
The box width may be less than the structure’s width when the structure is oriented at an angle to the prevailing currents.
This is the mean depth of water within the box.
Current speeds can be measured with a number of staff mounted or weighted electromagnetic or mechanical devices. For most projects, the value for this input will be between 0 and 11.8 in/sec.
The same methods described for Maximum tidal current speed or V_harmonic are appropriate for determining steady state current speeds. For most projects, the value for this input will be between 0 and 11.8 in/sec.
For purposes of evaluating long-term sediment accumulation of contaminants, an average annual temperature is appropriate. For most projects, the value for this input will be between 5 and 27.5 degrees C.
This can be measured using any one of the available field or laboratory pH meters. For most projects, the value for this input will be between 5 and 9 std. pH units.
Water hardness is important for determining the bioavailability and toxicity of metals in freshwaters. For most projects, the value for this input will be between 0 and 125 mg/L.
Salinity can be measured electrometrically using any one of a number of salinity and/or conductivity meters (Standard Method 2520) or by titration in the laboratory (SM 210C). Waters having a salinity < 2.0 PSU are considered freshwaters. For most projects, the value for this input will be between 0 and 40 ppt.
Copper is typically evaluated in a laboratory using inductively coupled plasma (ICP) (EPA Method 200.7). For most projects, the value for this input will be between 0 and 17 μg Cu/L.
Aquatic organisms are less sensitive to arsenic, zinc and chromium than they are to copper. For most projects, the value for this input will be between 0 and 360 μg As/L.
Dissolved chromium is determined using EPA Method 200.7. For most projects, the value for this input will be between 0 and 548.7 μg Cr/L.
Zinc is typically evaluated using inductively coupled plasma (ICP) (EPA Method 200.7). For most projects, the value for this input will be between 0 and 114.5 μg Zn/L.
Pentachlorophenol is not typically found outside of industrial areas or in some cases adjacent to railway rights of way. For most projects, the value for this input will be between 0 and 13 μg penta/L.
Rainfall data is available from the U.S. Natural Resources Conservation Service (NRCS) in soil surveys or from National Oceanographic and Atmospheric Agency (NOAA). For most projects, the value for this input will be between 0 and 98.4 in/year.
Trial runs with the model suggest that contaminated rainwater runoff from pressure treated wood structures during storm events has little effect on the predicted concentration of contaminants in water–unless unrealistic amounts of rainwater runoff are introduced to a small body of water whose flow does not respond to the storm. For most projects, the value for this input will be between 0 and 2 in/hour.
The length of the storm event is entered here. Because water body flows are not programmed (in the model) to increase during storm events, this input has little effect on predicted concentrations. For most projects, the value for this input will be between 0 and 36 hours.
TOC should be measured in sediments whenever either creosote or pentachlorophenol treated wood is proposed and a site specific assessment is required. For most projects, the value for this input will be between 0 and 5 percent.
The recommended value of 2.6 g/cm^3 should not be changed unless site specific information indicates otherwise. For most projects, the value for this input will be between 2 and 4.3 g/cm^3.
This endpoint should be determined for all projects involving either creosote or pentachlorophenol treated wood. For most projects, the value for this input will be between -250 and 500 mV.
This endpoint should be determined for all projects involving either creosote or pentachlorophenol treated wood. For most projects, the value for this input will be between 0.5 and 4 cm.
When required, triplicate samples should be analyzed in the laboratory using inductively coupled plasma (ICP) and EPA Method 6010 following a strong acid digestion. For most projects, the value for this input will be between 0 and 390 mg/kg.
When required, triplicate samples should be analyzed in the laboratory using inductively coupled plasma (ICP) and EPA method 6010 following a strong acid digestion. For most projects, the value for this input will be between 0 and 57 mg/kg.
When required, triplicate samples should be analyzed in the laboratory using inductively coupled plasma (ICP) and EPA Method 6010 following a strong acid digestion. For most projects, the value for this input will be between 0 and 260 mg/kg.
When required, triplicate samples should be analyzed in the laboratory using inductively coupled plasma (ICP) and EPA Method 6010 following a strong acid digestion. For most projects, the value for this input will be between 0 and 410 mg/kg.
When required, sediment concentrations of pentachlorophenol can be determined using EPA Method 8151 by gas chromatography with an electron capture detector (GC/ECD) to evaluate triplicate sediment samples. For most projects, the value for this input will be between 0 and 0.4 mg/kg.
Sediment concentrations of PAH can be determined using either high performance liquid chromatography (HPLC) with EPA Method 8310 or gas chromatography/mass spectrometry (GC/MS) analyses using EPA Method 8270. For most projects, the value for this input will be between 0 and 37.6 mg/kg.
Preservative loss rates from pressure treated wood decline with time with the highest losses occurring immediately after construction. Washington State acute water quality criterion (WQC) are one hour concentrations and a user entry of 0.5 days is recommended for comparison of predictions with acute criteria (this may be different in your region). Chronic criteria are generally a four day average and a user entry of 2.0 days is recommended for comparison with these criteria.
Default is 35 years with a minimum of 10 years.
Width of receiving channel of water. For projects crossing streams or those located in narrow channels, dilution zones are constrained by the boundary conditions imposed at the shoreline. The width of dilution zones will not exceed the channel width entered here.
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