Landforms

From Salish Sea Wiki
Revision as of 18:42, 19 June 2013 by Pcereghino (talk | contribs)
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On the wiki, we differentiate between pages describing sites and those describing places. Place pages can be about anything, from a oceanic sub-basin, to a county, to a pond. A site is a particular piece of the ecosystem based on current regional planning models:

Our approach suggests seven different types of ecosystem sites, each shaped by distinct processes, and potentially providing a distict suite of ecosystem services. We consider them each from mountain to sea:

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Headwaters

Headwaters are the steep foothill and mountain valleys, where precipitation falls as snow, and forestry is the primary land use. Landslides are a common distrubance.

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Lowland Watersheds

Lowland watersheds contain the streams that drain the low foothills and the glacial plateau. These landform are shaped by glaciers and most precipitation falls as rain. Many lowland watersheds are urbanizing rapidly.

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Floodplains

Floodplains form where the larger rivers and streams create and rework flat areas filled with their own alluvium. These are both the best places for intensive mechanized agriculture, the core of Chinook salmon habitat, and where risk of flooding is highest.

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River Deltas

Deltas form where large river floodplains enter marine waters. Tidal flows create fluctuating water levels. Most of our delta landscapes have been drained for agriculture, and lie below sea level protected by dikes. Deltas provide unique habitats for fish and birds, at the intersection of land, river and sea. Delta restoration projects are large and sometimes controversial.

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Embayments

Embayments are those protected places along the shoreline where wind waves are muted by aspect or spits, and collect muddy sediments, sometimes forming salt marsh, often at the mouths of streams. Around 800 large embayments have been found on historic maps (Simenstad et al 2011). These systems are less developed than beaches, and often receive concentrated watershed inputs.

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Beaches

Beaches form where sediment from eroding shorelines are pushed alongshore by waves, creating bluffs, benches, spits and lagoons. Beaches have been valued as residential property since time immemmorial, provide access to the wealth of the sea, but are vulnerable to storms. Beaches are organized into littoral cells--744 shoreline cells with eroding bluffs have been identified in Puget Sound (Cereghino et al 2012).

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Headlands

Rocky headlands emerge where bedrock is shallow along shoreines, along Juan de Fuca, San Juan Islands, and along the Seattle Fault. These dry stable shorelines contain pockets of beach. Our Bull Kelp forests are concentrated in these systems.

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Headwaters

We use place pages to define all other places. Humans define place using both natural and imaginary boundaries, as well as the extent of their settlements and development. Our places often contain a mixture of ecosystem sites, and define the focus of our management and governance.

Maps and Plans[edit]

We are currently storing images that describe ecosystem sites, in the ecosystem map category, displayed below. A future project will be to integrate this wiki with mapping systems that show ecosystem sites, like the Nearshore Portal