The Oregon Department of Environmental Quality (DEQ) is accepting public comments on the draft of The Tualatin Basin TMDL and WQMP until 5:00PM 11/30/2011. Mine are detailed below in a copy of the memo I sent to DEQ earlier today. I’ll have more to say about TMDLs, WQMPs, and a variety of other acronyms at a later date. Meanwhile the December “Drop Dead” date for the final draft of my book looms so I need to attend to that before anything else.
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To: Avis Newell / Oregon Department of Environmental Quality
From: Eric L. Lindstrom, EdD
Date: 11/29/2011
Re: Comments on TMDLs / Clean Water Services
It’s too bad there’s not a TMDL for something like “Total Stream Degradation.” Focusing on a few key and easily quantified characteristics of stream behavior such as nutrient loads, water temperature and so on is certainly a positive and necessary step in monitoring stream health. But until the actual drivers of these kinds of indices are addressed in some concrete regulatory form or another we won’t be dealing with the disease so much as we are its symptoms. For example, please regard the following photographs of Ball Creek.
Figure 1
These first two shots were taken above the culvert that directs the creek under 74th street in Tigard. These were taken on 5/2/2009, around 5:30 PM. A storm had passed over the Tualatin Hills area approximately an hour earlier. It was a good downpour but nothing for the record books by any means. The culvert lies less than 300 feet from the stream’s confluence with Fanno Creek. Figure 1 shows the receiving side of the flow while Figure 2 shows the outflow on the downstream side.
Figure 2
The next shot (Figure 3) was taken just below the south rim of PCCs southernmost parking lot (45N 26.169 W122 43.892 approx.) in an area that lies immediately below the a catchment that is designed to reduce, at least in part, the full force of the water flowing off the parking lot. (I believe that drainage from areas other than the parking lot comes through this place as well but have no precise data as to where from or how much. At this particular spot the channel is about four feet deep and six feet wide.
Figure 3
About 100 feet further down the slope the channel is roughly 12 feet wide and 7 feet deep. For scale the smaller rocks in the center of the photo range from baseball to basket ball size. The main channel has also been joined by three smaller but still impressive incisions entering from the west side. A fourth channel (Figure 4) is beginning to form on the east side as well.
Figure 4
I was so impressed by the dynamics of this site that I went to the trouble of working up a guess at the volume of silt that had to wash out of the first 100 feet of the single channel in order to leave this kind of scar tissue. Very approximately it came to 200 cubic yards. The college went operational in 1961 but I think this portion of the parking area wasn’t fully completed until the late 1990s. If that assumption and my rough numbers are even close, that means an average of better than 10 cubic yards of silt have been blown out of the first 100 feet of this channel every year. The quality and accuracy of my math notwithstanding, you don’t need a calculator to tell you that this open wound contributes a huge amount of silt and parking lot byproducts – oils, anti-freeze, brake dust etc. – to the main-stem flow of Fanno Creek every time it rains even moderately in the area. All you have to do is stand there once and see it in the flesh.
The conditions on Ball Creek aren’t unique. There are dozens of places such as this one in the Fanno Creek watershed alone and hundreds more throughout the Tualatin River Basin. The issues this kind of hydrology creates for the rest of the watershed are systemic and pernicious. The quantity of undesirable silt and other potentially damaging materials these open sores are sloughing off into the river must be absolutely stupendous. So too must be the damage that is being done to the biological communities downstream. None of the currently used indices directly measures the impacts of these festering sores on water quality. More importantly none of them provide a lever for getting at the specific stormwater runoff issues that literally and figuratively lie at the source of most of the river’s major biological health issues.
The ratio of pervious to impervious surface area is relatively easy to quantify, particularly in the urban areas where control of this relationship is most critical. The correlation between this ratio and the biological health of a stream and its watershed is both significant and well understood. Accordingly I am urging the adoption of a specific TMDL for Impervious Cover based on the Healthy Streams plan developed by Clean Water Services (pg. 59-60). At the minimum such a TMDL would provide leverage for the more direct control of stormwater runoff and all its associated issues. But it has the added advantage of providing a reliable surrogate for evaluating the biological health of the system as well.
The 303d list of biologically impaired streams in the Fanno Creek watershed does not include several tributaries whose impacts on the overall health of the creek are almost certainly significant. These include Sylvan Creek (all three of its upland stems), Columbia Creek, No Name Creek and the Bridlemile-Ivey creek complex in the northern headwaters of the system, and Bell and Derry Dell creeks in the southern reaches. Some of these creeks are very short in terms of total stream length, but all are heavily incised and becoming more so every day. Both Sylvan and Derry Dale creeks are of particular concern due to the landslides frequently associated with their behaviors. None are adequately monitored, if monitored at all. Until some semblance of measurement of their respective contributions to the overall health of the system is determined the full dimensions of Fanno Creek’s degradation will not be fully known. Accordingly I am requesting that these streams be covered under the pervious cover/biological health TMDL proposed above.
I have more photographs on hand that provide some evidence for the degree of degradation these streams endure and would be happy to make them available to DEQ if so desired. I would also be happy to provide further narrative and acquire additional photography on behalf of the DEQ should such action be deemed necessary for advancement of the Impervious Cover TMDL and the clean water cause. However photographs generally fail to adequately portray the full dimensions of the problem so I suggest a tour of some of these areas would prove to be even more useful in the decision making process. In such an event please let me know and I would be happy to provide some rough coordinates for some of the more typical and easily accessed places.
Respectfully submitted,
Eric L. Lindstrom, EdD – 11/28/2011
