Cannon Beach FMP Notes for City Council Topics 1. Grading Defined 7. Beach Access 2. Dune Grading for Views 8. Permitting 3. Vegetation 9. Mowing 4. Seasonality 10. Property-Values 5. Wildlife 11. Statewide Planning Goal 18 6. Slope 1. Grading Defined Foredune Grading for Views: Grading or sand movement necessary to maintain views or to prevent sand inundation, may be allowed for structures in active dune areas only if the area is committed to development and only as part of an overall plan for managing foredune grading. An approved Foredune Management Plan (FMP) is required for this activity. Currently, Cannon Beach does not limit the amount of sand that can be graded under a permit. Maintenance Grading: Grading that occurs in an area that was previously graded pursuant to an approved foredune grading plan and permit. Currently, Cannon Beach permits up to 2,500 cubic yards of maintenance grading under a single permit.1 Remedial Grading: Grading that occurs to only remove sand that is inundating a structure. Sand on the foredune may not be moved. DLCD provides guidance on how close to a structure this activity may occur. An approved FMP is not required for this type of grading. However, a permit from the City is required. 2. Dune Grading for Views Sand dunes provide important protection from waves and wind in coastal communities. Sand can also accumulate on the foredune, increasing its height and creating a desire for foredune management to maintaining ocean views. Grading foredunes to manage views is an optional activity under Oregon land use planning. Statewide Planning Goal 18 provides the requirements to allow foredune grading: the City is required to have a Foredune Management Plan for grading for views to be allowed. Six towns in Oregon currently have Foredune Management Plans: Cannon Beach, Seaside, Manzanita, Pacific City, Bayshore, and Nedonna Beach. Grading for views began in 1997 in Cannon Beach. The City is going through a process to update the existing Foredune Management Plan. Based on public comment at Planning Commission meetings, the 1 Cannon Beach Municipal Code 17.42.060(11)(c)) Planning Commission voted to send to City Council an updated plan that continues to allow grading for views and also made a recommendation that the policy of allowing dune grading for view be reconsidered. If the City elects to not allow grading for view preservation, then Comprehensive Plan policies and zoning ordinances need to be updated to reflect this change. If this City would like to continue to allow grading for view preservation, then an updated Foredune Management Plan will inform updates to the Comprehensive Plan and zoning ordinances. Resources and Guidance • Statewide Planning Goal 18 • DLCD 1989 Guidance Document • 6 cities with approved FMPs: Manzanita, Seaside, Cannon Beach, Pacific City, Nedonna Beach, and Bayshore 3. Vegetation As part of the update to the Foredune Management Plan, the City of Cannon Beach is considering what type of vegetation could and should be allowed to revegetate the dune after grading. This is an important question to consider because revegetation holds sand in place and stabilizes the dune and different types of grasses can lead to different dune shapes. Below is an overview of the types of grasses that could be used to revegetate the dunes and how each species could affect the dunes. There are three types of beach and dune grasses that could be used to revegetate the dunes: 1) European beach grass (Ammophila arenaria); 2) American beach grass (Ammophila breviligulata); and 3) American dune grass (Elymus mollis). European beach grass currently dominates the Cannon Beach dunes. During the Planning Commission session there was discussion about exploring the use of American beach grass or American dune grass for revegetation with the goal of creating lower dune heights. American dune grass (Elymus mollis) is the only species of the three that is native to the Oregon Coast. The image below describes how the different types of grasses affect the shape of sand dunes.2 3 Dr. Sally Hacker, Professor at Oregon State University who researches Oregon dune vegetation provided the following input via email: As you might know, the native dune grass Elymus (or Leymus) mollis historically was not abundant on our open coast sandy beaches and dunes (although it can grow densely in areas that are less exposed to wind and sand scouring such as on beaches in estuaries or behind existing foredunes). Thus, because it rarely grew/grows densely on the outer coast, it did/does not capture and stabilize sand very well. Thus, the reasons behind introducing the non-native beach grass species (see below). But the question is, when it does grow densely or is planted densely, will it stabilize sand and/or created foredunes? In addition, will it survive and grow well on an open coast beach even with a densely planted design? I think the answer will depend on the exposure of your beach to wind, sand scouring, waves, etc.4 When the two beach grass species, Ammophila arenaria (European species planted throughout the Pacific coast in the early to mid 1900s) and Ammophila breviligulata (East coast and Michigan lakes species originally planted near Fort Stevens and Long Beach in the mid 1930s and now the dominant grass in those areas) they grew very well, and became very dense. Sand capture experiments that we have conducted show that Ammophila arenaria is best at capturing sand, then A. breviligulata, and then E. mollis. This is the case in part because A. arenaria grows more densely than A. breviligulata or E. mollis. So the key to your question is to plant a dune grass species that can grow densely at your site. If you know that to be A. arenaria, 2 Zarnetske, et al (2012). Biophysical feedback mediates effects of invasive grasses on coastal dune shape. Ecology 93(6), 1439-1450. 3 This figure is adapted from Zarnetske, et al (2012). 4 Author note: As demonstrated by the 2018 DOGAMI Background Report, beaches in Cannon Beach have a high level of exposure to wind, sand scouring, and waves. then that would be the most conservative decision. That doesn’t mean that E. mollis (or A. breviligulata) would not also serve that purpose but you would have to experiment with the native to find that out (emphasis added).5 Andrea Pickart with U.S. Fish and Wildlife Service in California provided the following input regarding dune grasses. Please keep in mind her project utilized native dune grass in a different type of beach system that is not near developed areas, and she was not familiar with specific details in Cannon Beach. Hi all, first some clarification. American beachgrass is Ammophila breviligulata, which is native to the dunes of east coast and great lakes, but has been widely planted in Oregon and Washington. There has been extensive research out of OSU showing that A. breviligulata is replacing A. arenaria, and that it creates lower foredunes. I'm thinking that Denise is referring to American DUNE grass, Elymus mollis (aka Leymus mollis) which is native to west coast. We have used it extensively in planting at the North Spit. It does not trap sand as efficiently as A. arenaria or A. breviligulata and forms a less steep foredune (some argue lower, but that hasn't really been shown empirically, and it is on our highest foredunes here). We use E. mollis because it is native (biodiversity), and it allows for natural foredune processes, which includes allowing some sand to bypass the foredune. We are working in natural systems with extensive back dune areas. From your description, with infrastructure directly behind the foredune, it sounds like you do not want any sand movement, nor are you trying to support a natural system. Some of our Elymus foredunes are vegetated quite densely and show little sand movement, but it is variable so if your goal is to freeze your foredune, you probably want to stick with A. arenaria.6 Vegetation choices must be based on the desired outcome. If the goal is to hold the sand in place to protect structures from sand inundation, then it is important utilize grass that grows densely and has physical characteristics that make it effective at trapping sand. It is necessary to consider where the sand would go if it is not held in place by the grass. It could end up in somebody’s home. According to data collected by Dr. Hacker, American beach grass can be found along the Oregon Coast. If there is interest in using this type of grass, it may be worthwhile to gather more information on where this grass can be found and how stable those dunes are. The grass may define the season in which grading is permitted. European beach grass can be planted in cooler weather. However, native grasses die back in winter and they need the summer to establish. This will impact decisions about which season to allow grading to occur. If needed, a temporary measure, such as jute matting, could be used. All grasses are perennial, meaning that they will come back each year after being dormant (or mostly dormant) in the winter months. European beach grass has been successfully planted and established in Cannon Beach in the winter months. The native grass experiences less growth during the winter months, so temporary measures may need to be utilized to stabilize dunes after grading if this vegetation is selected for replanting. 5 Hacker (2018). Personal Communication. February 15, 2018. 6 Pickart (2018). Personal Communication. February 5, 2018. Resources and Guidance • Zarnetske, et al (2012). Biophysical feedback mediates effects of invasive grasses on coastal dune shape.