Saturday, March 26, 2011

Stream Keepers

With April fast approaching plans are in the process for the cleanup of Knarston Creek at the end of Normarel Rd adjacent to the recently logged woodlot. The date set for the cleanup is the third Saturday of April the 16th at 9am.

Over the past month we have seen high flows on all the streams again due to high rain events. As said in last months article this has caused some concern for the Chum salmon eggs buried in the substrate. With runs being unusually low last fall over the entire coast our concerns are for the main spawning creeks of Nanoose and Bonnel creeks. Nanoose Creek is relatively stable in regard to the gravel during periods of high flows so we are not too worried for this system. The same cannot be said for Bonnel. With a severely impacted watershed flash floods are common all through the winter bringing large amounts of sediment downstream filling in pools while scouring out new ones. Some eggs will be washed out while others will be buried deeper in the gravel making it difficult for the fry to wiggle out. Only time will tell. Over the past month we have been out doing some Willow staking to try and stabilize some of the newly formed gravel bars and erosion sites, this takes the form of using large diameter cuttings and driving them as deep as possible into the substrate down into the water table, this will allow them to root well while supporting vegetative growth above ground. One site we went to was alongside the new flood control structure on Knarston Creek, as this is a highly visible site we were concerned with the barren nature of the site left after construction was complete. Due to the large amount of rock used the planting of trees is restricted to small polygons away from the rock. Over time nature will revegate this site returning it to a more visually pleasing site. The control structure has been working well to prevent flooding below Lantzville road over the winter bringing relief for the residents. Some concern has been expressed as to the beach with the creation of a new seasonal flow regime from the outlet. While the water itself does not pose any problems for the beach but the new scouring of the foreshore habitat has disrupted the foreshore habitat for all the animals living their and will take time to readjust to these new environmental conditions. This area of foreshore is now a Clam lease for Snaw Naw As First Nations. With the high levels of coli form counts along the foreshore from the Hammond Bay Road sewer pumping station all Clams and other shellfish are not fit for human consumption all along the foreshore of Lantzville unless placed in areas of clean water and allowed to flush clean. In the old days we had septic systems, yes some along the foreshore leaked directly into the foreshore habitat especially those installed along the rocky sections of beach, now we have the big pipe solution which has moved the problem further down to the big outlet pumping into the ocean. This takes longer to flow back along the beach with the currents and tide but the results for the foreshore are the same.

The ocean is very forgiving and if it is only waste can to a certain extent handle sewage disposal but as with all sewer systems it is what else is flushed down the toilet and drains, 2,000 flushes always blue, harsh chemical cleaners, bleach etc, and any thing else, out of site out of mind. So please think before you flush or drain for the sake of the beach and all its inhabitants.

March Log

This past month we have been busy with tree planting and doing more stream surveys to line up our coming activities for the next few months. Bloods Creek has seen some flooding since the last snowfall though no major disruption to the habitat has occurred. Knarston Creek’s flood control structure seems to be alleviating the flooding for those that live downstream of Lantzville road while in the upper watershed some small erosion sites have been identified and will get some attention over the next month or so. Small erosion sites are a natural process of stream morphology [fluvial geomorphology to be technical] what this means is that when you look at a stream you tend to see it in a relatively stable state but unless in flood state you do not tend to see how the hydraulic effect of flowing water is changing constantly what we term as the stream bed and banks. Small particles are constantly being eroded from the banks and the streambed as the water flows downstream. Consequently small particles of suspended sediment are constantly flowing downstream, depositing when encountering barriers. These barriers can be as small as gravel and as big as log jams. Good old gravity tends to allow the banks to ever so slowly creep down allowing for the water to carry away material, this can also occur when wildlife [or humans] cross the stream eroding the banks. Even the action of small animals burrowing into the banks to create homes or in the search of food creates erosion. So as you can see erosion is a natural occurrence of a healthy stream environment. Nature’s way is to grow plants where by the roots can hold the bank material in place slowing the erosion process down. When we find eroded banks we have to assess whether it needs some plants or do we just leave it, if we decide to intervene we will do what has become called Bio-Engineering, the use of plant’s to remediate erosion sites as apposed to bringing in machinery and loads of rock to armour the banks. Over time we have realised that plant’s will do a more natural job of alleviating the erosion than riprap. Rocks tend to be the hard engineering solution so often used because it is easy and satisfies our need for control of our environment. Using plant’s on the other hand is working with the ecosystem using its own methods to help to heal the site while providing habitat and as we often find out when using Willow providing food for the Beaver. One of our first Willow plantings was at a site used to transport logs across a stream from a small clear-cut, as you can imagine this made a big mess. We went in and drove stakes into the banks and wove branches much like basket weaving to provide a vegetative barrier to the forces of the flow while softly dissipating the energy against the banks. Rip-rap was all we heard, that is the only way to go, well within a year the stakes had taken and the weaving had collected sediment [Barrier] and along with the planting of trees we achieved bank stability without the ugly look of rip-rap which in most cases tends to bounce the energy of the water around the channel usually creating more erosion downstream. Back to the Beaver, he or she taught us our first lesson in planting Willow stakes, shade being important to the stream we had left most of the stakes full length with about 3 feet in the substrate and a equal amount or more above grade, along came the Beaver and chewed off all the stakes down to around a foot tall then left them alone. What he had done was limit the vegetative growth above ground while allowing the roots to fully form without the desiccation [drying out] of the stakes by having too much growth on top. I personally think he was thinking of the lovely lunches he would have when all that new growth would come over the following years.

March will see the return of the Herring to our shores, which will hatch out just in time for our young Salmon who will be leaving their natal streams. The young Herring will provide a huge biomass of food to help them grow into healthy Wild Salmon before heading out further into the Pacific to complete their life cycle.

April will be the month we will cleanup upper Knarston, date and time will be in the April Log, hope to see you their.

Best Fishes John Dunn