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Haines Suggestions on Bayshore Canal

Mid-Coast Watersheds Council
157 NW15th Unit1
Newport.Oregon 97365
13 January 2004

Lloyd Haines
PO Box 2427
Waldport, OR 97394

Lloyd:

I am the coordinator of the MidCoast Wetlands Council (MCWC). My duties include meeting with owners of stream- and waterfront property about restoration and enhancement of their aquatic habitats. In this capacity I have visited Bayshore twice and toured your canal with your canal committee. Based on these visits (Dec. 8 and Dec. 15, 2003) I believe I can offer some advice concerning issues with your canal system. This advice is from me personally,and should not be construed as from the MCWC. The Council as a whole has not reviewed this advice.

My comments relate to five apparent issues: (I) algal proliferation in the canal system, (II) maintenance of the drainage ditch from the tennis court area to the head of the main canal, (III) erosion drainage to canal-side properties, (IV) canal depth and (V) "the plug."

First, I will comment that the layout of the canal system is not ideal, and there is no magic solution that will meet everyone's desires, without damaging anyone else's property. Second I will describe some of the conditions I observed that may be relevant to these issues:

1. Because I visited in December I did not see the worst of seasonal algae blooms, but enough algae mats persisted to convince me that the problem is real.

2. In many localities yard fertilizer is an important source of nutrients in runoff; but this does not appear to be the case in Bayshore.

3. I noted that the canal bottom a short distance above the plug was heavily colonized with sand shrimp and other burrowing organisms. These animals play an important role in the health of the canal. Their burros conduct -water and oxygen into the substrate, and reduce the development of anoxic conditions.

4. I noted a number of Dungeness Crab shells in the canal and on the banks. It was not clear how many of these came from free living crabs, and how many were discarded from the nearby residences, or were kept in live boxes; never-the-less, it appears that the canal is still capable of being crab habitat.

5. The upper canal areas I visited (head of the main canal, and lower side canal) have generally well-vegetated sides.

6. On the lower section, between the plug and the first side canal, bank vegetation was good overall, but there were a number of sections with inadequate vegetation and some bank erosion apparent.

7. The drainage ditch that runs from the Tennis Court area down to the bead of the main canal was well vegetated with freshwater aquatic plants. and had some shrubbery growing into it from the sides. That said, I believe there are some modest steps that can be taken to improve conditions in the canal system at modest expense, and with minimal risk. Do not expect these to solve all problems,but they should alleviate some.

I. Algal proliferation: Some basic ecology heavy algal growth occurs when and only when environmental conditions are favorable for algae. The species of algae that form mats on the canal bottom or surface are salt-tolerant, grow most luxuriantly in warm temperatures. and need adequate nutrients (nitrogen and phosphorus). The typical pattern of maximum
growth in late summer and fall reflects higher temperatures and minimum nutrient flushing. To reduce algal proliferation, the best thing to do is reduce the nutrient supply available to the algae. Most other approaches just treat symptoms. rather than causes. Several things can be done to reduce .the nutrient supply.

A The ideal approach is to cut the nutrients off at the source. This can be difficult and expensive. but several things help.

(1) Keeping all septic systems in good working condition will help. Upgrading of older systems will also help.
(2) One of the Canal Committee members commented about gulls roosting on roofs, and then their droppings washing down the gutter systems. which tend to be piped directly into the canals. If the gutter runoff could be instead piped into sumps within the yards, these nutrients would not get to the canals. This would be important mainly for canal-side homes. The amount of nutrients involved is not great but solving the overall problem will take a lot of small incremental steps.
(3) During my visits a lot of dog manure was visible along some roadsides near the canals. Establishment of dog-walking areas further from the canals or clean-up rules might help. Again this is one of many small steps that can be part of the solution.

B. The next approach is to encourage plants that are less objectionable than the algae to grow, because they will use some of the nutrients that otherwise would promote algal growth. Three things in particular seem appropriate for Bayshore.

(1). Vegetation in the drainage ditch from the Tennis Court area can be managed to remove some nutrients from the runoff. This is discussed further in the next section.
(2) The salt-tolerant grasses and other vegetation that grows on the lower canal banks compete with the algae for nutrients. Therefore, increasing the
amount of such vegetation will reduce the nutrients available to support
algae. This also will help with erosion control (below).
(3) Canal cleaning. During our visit, quite a bit of dead grass was seen stranded on the banks at the head of the main canal. This evidently was shed by grass plants along the canal and floated, then wind-blown to this location. A person with a rake and a wheelbarrow could rake up and remove this accumulation a few times per year, and thus physically remove nutrients that would otherwise contribute to the next year's algae bloom.

II. Maintenance of the drainage ditch from the tennis court area to the head of the main canal. This ditch is important for avoiding water accumulation around a number of residences, but appears to be a source of nutrients to the canal system.

A. I recommend leaving this ditch vegetated, but managing the vegetation in it, both to reduce potential for erosion, and so that vegetation will use up more of the nutrients that are draining toward the canal. On the other hand, too much vegetation will eventually plug the ditch.
B. I therefore recommend occasional mowing of the vegetation in the ditch. A large wheeled
mower likely is necessary to negotiate the ditch bottom. Clippings from
the mowing should be removed from the ditch, otherwise they will rot and return the nutrients back into the runoff water. Annual or twice-annual mowings should be adequate. Some shrubbery along the ditch also will need pruned.

III. Erosion damage to canal-side properties. It appeared during my visits that most of the canal side properties were reasonably well-protected from erosion by well-vegetated banks. However, a number, particularly low in the system, have inadequately vegetated banks that have recently sloughed, and cut back into the lots. In some cases this threatens to make lots unbuildable. In my opinion, good vegetation coverage can prevent erosion
except in the places exposed to the heaviest current or wave action. In some places, more substantial riprap or sea-walls may be necessary.

A. I recommend planting as much of the exposed sand substrate on the canal banks as feasible with salt-tolerant grasses and other salt-marsh plants. A lot of this can probably be done by moving plugs of grasses from existing stands within the canal system. This will not only reduce erosion risk, but will help to deal with excess nutrients, as described above in section 1. C.(2) above.
B. In some spots some sort of low sea-wall or riprap development may be necessary to prevent erosion or repair existing problems. In these spots I strongly recommend locating such protection a few feet back from the canal edge so that some sand accretion and vegetation development can occur between the canal and wall. A few existing examples show this in the lower canal. This has several benefits: the sand and vegetation protects the wall, helps use up nutrients, reduces current velocities, and provides wildlife habitat.

IV. Canal depth. Clearly, the canal system has filled in somewhat since it was built. This is inevitable in the loose-sand substrates of Bayshore. Some owners are justifiably concerned about this filling in. Before undertaking any actions to deepen canals, however the association needs to come to an agreement on how they want the canals to function. The association also needs to consider very carefully how any deepening actions will affect erosion of canal banks. I do have recommendations.

A Erosion prevention as described in Section III above should be undertaken before any deepening projects.
B. It was apparent during my low-tide visit that the canal depth is very uneven. A very shallow area exists just upstream of the plug, and the canal is fairly shallow up to the first side canal. The side canals are deeper. The upper end of the main canal is very shallow. I recommend assessing the depth throughout the system before beginning any deepening. This could be done by a person in waders at low tide, with a graduated staff: or could be surveyed. This is likely to reduce costs, by restricting any deepening to the places that actually need it, and by giving contractors better information to use in preparing bids. Uncertainty tends to increase bid prices.

V. The plug. In a tidal system, the size and placement of a culvert greatly affects hydrology.

A. The current culvert is placed well above low tide, which prevents complete drainage at low tide and abets the canal filling in.
B. The size of the culvert is insufficient to allow complete filling at high tide: the tide changes, and begins to ebb before the water level equalizes across the plug. This is not necessarily a bad thing, as it probably reduces erosion on storm-tide events.
C. I recommend that before doing any modifications to the plug or culvert you complete the steps in III (above) to reduce erosion risk.
D. If you want to deepen the canal, you will also need to set the culvert deeper in the plug, to allow more complete flushing.
E. If you want to allow the water levels in the canal to rise and fall freely with the tides in the bay, you will need to replace the culvert with a larger one, or a bridge (or just remove the plug).

VI. Steps to proceed. I have a few procedural recommendations that may help accomplish what you need.

A Come to agreement among yourselves on what you want the system to look like. How deep do you want the canal? Do you want boat access? How far up? How much algae growth is acceptable? There are well-worked out procedures for finding consensus. It may be worthwhile to investigate these.
B. I recommend strongly that you investigate permit requirements before each step you undertake, and do not do anything without the appropriate permits. Proceeding otherwise is inviting trouble. .This said, expect a slow and frustrating permit process if you choose to make major changes. You should not need permits for steps that are just data collection (e.g., surveying canal depth) or vegetation management (mowing the ditch, planting canal banks). For anything else, investigate permit needs.
C. For anything major - canal deepening, or plug modifications -hire the expertise of an engineer with experience in tidal situations. Do not just go do it.