Mid-19 Century Stream Channels and Wetlands Interpreted from Archival

Mid-19th century stream channels and wetlands interpreted from archival sources for three north Puget Sound estuaries

Report Prepared for:

Skagit System Cooperative P.O. Box 368 La Conner, WA 98257

Bullitt Foundation 1212 Minor Avenue Seattle, WA 98101

Skagit Watershed Council 407 Main Street, Suite 205 P. O. Box 2856 Mount Vernon, WA 98273

Report Prepared by:

Brian Collins bcollins@u.washington.edu Department of Geological Sciences Box 351310 University of Washington Seattle, WA 98195

August 1, 2000

Summary

This report presents Arc/Info GIS maps of historic (pre-European settlement, or approximately 1860) channels and wetlands in the Skagit-Samish delta and Stillaguamish estuary, and the Snohomish River valley and explains the methods used to create the maps.

Primary sources of information are: (1) U. S. Coast & Geodetic Survey (USC&GS) charts from 1884 to 1893 (Figure 3); (2) General Land Office (GLO) maps from 1866 to

1877; (3) U. S. Army Corps of Engineers maps; (4) topographic maps; (5) field notes from the GLO surveys; (6) soil surveys, from as early as 1909; (7) government reports, and (8) accounts by settlers. The GLO field notes were an especially important source of information supplemental to map sources. At over 800 points, the notes provided diameter, species, and distance to nearly 1,400 witness trees; general descriptions of vegetation and hydrology; and quantitative observations on water depths and flooding.

Estuarine wetlands, mapped by use of various sources and methods, were extensive in the floodplains of each of the three rivers, accounting for at least one-half of land area in each area. The Snohomish River valley and Skagit-Samish delta also had extensive freshwater wetlands (freshwater wetlands include riverine-tidal areas in which tidal backwater augmented flooding effects). Freshwater wetland was more than four times the extent of estuarine wetlands in the Snohomish and the two were equal in the Skagit-

Samish delta. Field observations from the GLO notes allow estimates of seasonal inundation in some of the larger marshes. For example, Marshland, a 1,900 ha wetland on

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the floodplain of the Snohomish River, was inundated in February 1871 in at least half

and as much as 90% of its area to a depth of more than two-thirds of a meter. Freshwater

wetlands on the Stillaguamish delta were less extensive than on the Skagit-Samish delta and the Snohomish valley.

Each estuary had numerous distributary and blind-tidal channels. Channel types mapped are: mainstem, distributary, blind-tidal, connecting, floodplain slough, and tributary. For each channel type, segments are broken out in the estuarine-emergent, estuarine-scrub- shrub, tidal-freshwater, and freshwater zones and area summed for each. The Skagit-

Samish delta, because of its diverging-spreading form, is dominated by estuarine channels, while the confined and low-gradient Snohomish River estuary is dominated by tidal- freshwater distributary channels. Channels in the confined Stillaguamish valley are also dominantly estuarine but have a relatively small area because of the relatively steep valley.

Diking, ditching, and filling greatly diminished the extent of freshwater and estuarine wetlands and blind tidal channels on each of the three river deltas. In the Skagit and Stil- laguamish rivers, nearly all wetlands had been diked, drained, and ditched by early in the

20th century. In the Snohomish valley, change was more gradual but nonetheless nearly all wetlands had been altered by the middle of the 20th century.

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Map 1

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Map 2

Table of Contents

Summary……………………………………………………………………..i Map 1…………………………………………………………………...…..iii Map 2…………………………………………………………………….…iv

Table of Contents………………………………………………………...….v List of Maps………………………………………………………...……….v List of Tables………………………………………………………………..vi List of Figures……………………………………………………...……….vi

Introduction………………………………………………………………….1

Methods and Sources of Data………………………………………………..4 Witness Tree Records from GLO Notes……………………………...4 Digitizing Methods and Primary Map Sources……………………...10 Approach to Creating “Historic Conditions” Map…………………..17

Explanation of Historic Conditions Maps………………………………….22 Snohomish River…………………………………………………….22 Stillaguamish River………………………………………………….36 Skagit-Samish River Deltas…………………………………………39

Historic Area of Wetlands and Channels…………………………………..52 Areal Extent of Wetlands……………………………………………52 Channel Area………………………………………………………...53

Habitat Change……………………………………………………………..59

References Cited…………………………………………………………...64

List of Maps

1. Wetlands and channels on the Skagit-Samish River deltas, as interpreted from archival materials, ~1860………………………….iii

2. Wetlands and channels in the Snohomish River valley, as interpreted from archival materials, ~1860………………………………..……..iv p. v

List of Tables

1. Trees and shrubs in GLO field notes………………………………..15 2. Elevation limits of tidal marsh………………………………………21 3. Characteristics of bearing trees in historic Snohomish wetlands……29 4. Characteristics of bearing trees in historic Stillaguamish wetlands…38 5. Characteristics of bearing trees in historic Skagit-Samish wetlands..44 6. Land areas in ~1860 for the three study areas……………………….52 7. Channel areas in ~1860 for the three study areas…………………...56

List of Figures

1. Location of study areas……………………………………………….8 2. Place names referred to in study areas………………………………..9 3. Location of GLO sample points……………………………………..19 4. Year of survey for GLO cadastral survey maps……………………..20 5. USC&GS map source information………………………………….21 6. Historic topographic maps used in analysis…………………………22 7. Distribution of GLO witness trees in Snohomish valley marshes…..30 8. Diameter of GLO witness trees in Snohomish valley marshes……...32 9. Abundance of riparian and floodplain GLO bearing tree species in the Snohomish valley……………………………………………..33 10. Diameter of GLO witness trees in Snohomish valley riparian and floodplain forests………………………………………………..35 11. Map sources for Skagit-Samish and Stillaguamish wetlands……….46 12. Distribution of tree species in major freshwater wetlands on the Skagit-Samish delta…………………………………………..47 13. Diameters of freshwater wetland tree species, from GLO witness tree notes, on the Skagit-Samish delta……………………..48 14. Abundance of witness tree species on the Skagit-Samish delta……..49 15. Diameters of tree species from GLO witness tree records………… on the Skagit-Samish delta…………………………………………..51 16. Extent of map units in the study areas in ~1860…………………….57 17. Area of channels within vegetation zones in ~1860………………...58 18. Skagit-Samish and Stillaguamish deltas in ~1915 and ~1945………61 19. Snohomish River valley in ~1900 and ~1950……………………….62

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Introduction

The objective of this report is to document the approach taken in producing GIS maps showing historic channels and wetlands, as interpreted from archival sources, in the deltas and estuaries of the Skagit-Samish, Stillaguamish, and Snohomish rivers, three large rivers in northern Puget Sound (Fig. 1). “Historic” refers to immediately prior to significant changes by Euro-American settlers. In the study areas, this is approximately 1860.

This is a pilot project for a larger effort as part of the Puget Sound River History Project at the University of Washington to reconstruct historic river environments throughout the

Puget Lowland. This report accompanies v. 1.0 of these GIS maps, which will be revised as additional information becomes available. The maps are not based on site-specific field investigations, but are interpretations from a variety of historical sources of varying accuracy, and many boundaries are generalized or extrapolated, as described in the report.

The Skagit and Samish rivers share the Skagit River delta, which is fronted, in a north-to- south order, by Samish Bay, Padilla Bay, and Skagit Bay, respectively (Fig. 2). Tidal marshes fringing the south end of the Skagit River delta are contiguous with those of the

Stillaguamish River to the south. The Stillaguamish River formerly flowed both into

Skagit Bay to the north and Port Susan to the south, but has since early this century flowed into Port Susan. The Snohomish River enters Possession Sound at the city of

Everett (Fig. 2).

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Figure 1. Location of the Skagit, Stillaguamish, and Snohomish basins in the Puget

Sound basin. Study areas are shown by hatching.

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Figure 2. Modern place names referred to in report.

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The Samish, Skagit, Stillaguamish, and Snohomish river basins are 275 km2, 7,800 km2,

1,770 km2, and 4,640 km2 in area, respectively (Ames and Bucknell, 1981). I defined the

study areas in the three rivers to include the extent of tidal backwater influence. The upper limit of tidal influence in the Samish, Skagit, Stillaguamish, and Snohomish rivers is approximately river kilometer 6 (RM 4), 13 (RM 8), 10 (RM 6), and 27 (RM 17).

Primary archival map sources include: the federal General Land Office (GLO) cadastral surveys (1866 – 1877); an Army Corps of Engineers (USACOE) map of a portion of the

Skagit delta (1898); and U. S. Coast & Geodetic Survey (USC&GS; 1886 – 1893) charts.

I also made use of field notes from the cadastral surveys, which include observations on vegetation and water features. Using these sources, I mapped channels, and classified and mapped tidal wetlands and freshwater wetlands based on the system of Cowardin et al.

(1985). These map units can serve as indicators of aquatic habitat for salmonids (Hayman et al., 1996). I also used archival topographic maps from the beginning and middle of the

20th century to display changes to wetlands and channels.

Methods and Sources of Data

Witness Tree Records from Land Survey Notes

White (1991) includes a compilation of instructions given to federal land surveyors in the

mid-19th century. Instructions that were current for the study area (see White, 1991) were

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published in 1851, 1855, and 1864;1 the next revision was in 1881. While some details of these instructions varied through time, all instructions indicated for surveyors to establish

reference points at the corners of mile-square sections and half way between corners

(“quarter section” points). At each reference point, they were to establish a monument and measure distance (in links) and the compass direction to “bearing” or “witness” trees near to the survey point. At section corners, surveyors were to make use of four witness trees, one in each section. Where trees were sparse, surveyors may have referenced less than four trees. At quarter section boundaries, they were to document two witness trees,

“in opposite directions” (p. 440, White, 1991). If there were no trees nearby, surveyors were to build a mound of earth. In practice, in the study area, in some wetland locations it was not possible to establish a mound because of deep standing water. In their field notes, surveyors were to record the diameter and species of each witness tree (“the kind of tree and the diameter of each are facts to be distinctly set forth,” p. 440, White, 1991), and the distance and bearing to it.

In addition to these regularly-spaced points, surveyors also established “meander corner points” (p. 461, White, 1991) at the banks of navigable rivers and sloughs where section lines intersected them. Two bearing trees were to be established at such meander corner points. Such points were to be established along all navigable streams, which were

1 “Instructions to the Surveyor General of Oregon; Being a Manual for Field Operations,” Washington, D.C., 1851; reprinted as pp. 433-456 in White, 1991; “Instructions to the Surveyors General of Public Lands of the United States, for those Surveying Districts Established in and Since the Year 1850; Contain- ing also a Manual of Instructions to Regulate the Field Operations of Deputy Surveyors, Illustrated by Dia- grams,” 1855, Washington, D. C., p. 457-500 in White, 1991; “Instructions to the Surveyors General of the United States, Relating to Their Duties and to the Field Operations of Deputy Surveyors,” Washington, D. C., 1864; reprinted as p. 501-510 in White, 1991. These versions of the Instructions to Surveyors are here- after abbreviated in referencing as “Instructions.” p. 5

mapped by “meandering.” Meandering consisted of taking bearings and measuring distances along both channel banks, and periodically measuring the channel width (p. 464,

White, 1991). All “lakes and deep ponds of the area of twenty-five acres and upwards” were also to be meandered. I refer to these meander corner points as “riparian,” to distinguish them from the points which were established at corners and quarter corners, which

I refer to as “floodplain” unless they happen to be immediately adjacent to a stream.

Some important details of the land surveyors’ field protocols vary between the different instructions issued by the Surveyor General, or in some cases are ambiguous. For example, the criteria for selecting trees is not entirely clear. Slightly earlier instructions, elsewhere in the nation (e.g., 1850 instructions from the Surveyor General’s Office of Flor- ida), instructed surveyors to use “the nearest tree in each section” as witness trees (p. 382,

White, 1991). Elsewhere, earlier instructions were to select for bearing trees those “which are the soundest and most thrifty in appearance and of the size and kinds of trees which experience teaches will be the most permanent and lasting” (“General Instructions to

Deputy Surveyors,” Little Rock, Arkansas, 1843; p. 333, White, 1991). I have assumed that surveyors would have primarily selected trees that meet the criteria of being in opposite directions in the case of section quarter corners, or in four quadrants in the case of section corners. I assume that proximity is the secondary criterion, but that some excep- tions would have been made by some surveyors in order to choose sturdier trees that might be somewhat farther from the survey point.

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Also unambiguous are criteria for the minimum size of bearing trees and their maximum

allowable distance from the survey point. The 1864 Instructions require trees to be “not

less than two and a half inches in diameter” and “within 300 links [60.36 m] of the corner” (p. 505, White, 1991). However, some earlier instructions are that “trees are to be alive and not less than five inches in diameter” (“General Instructions, Office of the Sur- veyor General of Wisconsin and Iowa,” 1846; p. 341, White, 1991). However, in the study area, three inches for practical purposes appears to have been used as a criterion for minimum diameter; only one of 951 trees for which diameter was recorded was less than three inches in diameter. In the study area, the 300-link-distance guideline from the 1864 instructions was not strictly followed; 24 of 944 trees (2.5%) are more than 300 links distant, with the greatest distance being 1,094 links (220.11 m).

Because of the minimum-size requirement, all other criteria aside, bearing trees would under-represent smaller-diameter species (e.g., vine maple [Acer circinatum], willow

[Salix spp.]). The potential for the most proximal trees to be passed up in favor of durable or hardy trees could also bias the data away from smaller trees. However, while imperfect data for quantitative analysis, bearing trees are generally considered to reasonably represent the distribution of tree species and diameters (see Whitney, 1996, p. 18-29, for discussion). Because of the biases against smaller trees, it is reasonable to assume that using the bearing tree records to characterize tree frequency (i.e., the percent of all trees accounted for by any given species) would under-represent smaller tree species. On the other hand, it also follows that the bearing tree records would reasonably accurately char-

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acterize basal area (i.e., the percent of the sum of cross-sectional area of all trees accounted for by the cross-sectional area of any one species).

To evaluate this hypothesis, we reoccupied survey points that had been established by land surveyors in 1873 in the Nisqually River valley (see Collins and Montgomery,

2000). A mature floodplain forest exists in that study area, which is contained within the

Fort Lewis military reservation and the Nisqually Indian Reservation. At each of 26 points, we established bearing trees following our interpretation of the instructions to surveyors current in 1873. In addition, we also recorded the species and diameter of all trees larger than 0.01m in diameter in a 314.2 m2 plot at the survey point. Comparing the bearing tree data to the plot data confirmed the hypothesis that the bearing trees are a good estimate of species distribution by basal area.

For the present study, for all witness trees, I recorded into a spreadsheet species, diameter, and distance from the survey point. Points were plotted on 7.5’ topographic maps and digitized. I identified 823 locations and 1,388 trees (Fig. 3). The GIS coverage created from these points includes average diameter, distance, and relative abundance of dominant species. The GLO notes identify trees using common names. Table 1 shows names and our best guess at the species they represent; the species was fairly obvious in most cases. “Balm of Gilead,” taken to refer to balsam poplar (Populus balsamifera), does not occur in the study area, and was assumed to be misidentified black cottonwood (Populus trichocarpa). A primary use of the bearing tree data is to use average distance to bearing trees as an approximate relative index of tree spacing, for comparing one map area to an-

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other. For this purpose, any species or size biases should not matter. I did not attempt to

convert the distances measured to trees into forest density, because the sample size at

each point was small.

Table 1. Trees and shrubs recorded as witness trees in GLO field notes, and probable

common and scientific names. Trees are listed in decreasing frequency of occurrence.

Common Name Probable Scientific Name

Alder Red alder (Alnus rubra) Spruce Sitka spruce (Picea stchensis) Willow Willow spp. (Salix spp.) Cedar Western redcedar (Thuja plicata) Hemlock Western hemlock (Tsuga heterophylla) Crabapple Pacific crabapple (Pyrus fusca) Maple Bigleaf maple (Acer macrophyllum) Fir Douglas-fir (Pseudotsuga menziesii) Birch Paper birch (Betula papyrifera) Vine maple Vine maple (Acer circinatum) Cottonwood Black cottonwood (Populus trichocarpa) Juniper Common juniper (Juniperus communis) Balm Black cottonwood (Populus trichocarpa) Barberry, Bearberry Unknown White fir Fir spp. (Abies spp.) Pine Shore pine (Pinus contorta) Yew Pacific yew (Taxus brevifolia) Hazel California hazel (Corylus cornuta californica) Cherry Bitter cherry (Prunus emarginata) Elder Elderberry spp. (Sambucus spp.) Dogwood Dogwood spp. (Cornus spp.)

The surveyors were also to make fairly exhaustive notes of land and water features they

encountered. For example, “land objects” to be noted included major changes to vegeta-

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tive community, streams and marshes,2 and the width of all “water objects” was to measured.3 Springs, lakes and ponds and their depths, the timber and undergrowth, bottom lands, visual signs of seasonal water inundation, and improvements were all among the information to be noted along section lines. In practice, the completeness of this information varies from surveyor to surveyor, and so cannot be assumed to be complete, but it provides important secondary data for interpreting the historic landscape. The information was particularly useful in describing wetlands. For example, by noting the date at which surveyors’ observations of water depth were made, combined with their notes on indirect indicators of seasonal water depths, it was possible to make a digital file of points and arcs describing summer and winter water depths. In combination with vegetation observations, this was useful for describing wetlands.

Digitizing Methods and Primary Map Sources

We digitized full-scale (one inch equals 40 chains, or one-half mile) copies of GLO maps

(Fig. 4) in ARC INFO using the on-screen “heads up” method. We geo-referenced to section corners, and used UTM Zone 10 coordinates to project all coverages. We made

2 “The distance at which the line first intersects and leaves every settler’s claim and improvement; prairie, river, creek, or other “bottom;” or swamp, marsh, grove, and wind fall, with the course of the same at both points of intersection; also the distances at which you begin to ascend, arrive at the top, begin to descend, and reach the foot of all remarkable hills and ridges, with their courses, and estimated height, in feet, above the level land of the surrounding country, or above the bottom lands, ravines, or waters near which they are situated (Instructions to the Surveyors General of Public Lands of the United States, for those Surveying Districts Established in and Since the Year 1850; Containing, also, A Manual of Instructions to Regulate the Field Operations of Deputy Surveyors, Illustrated by Diagrams, 1855, p. 466 in White, 1991) 3 “All rivers, creeks, and smaller streams of water which the line crosses; the distance on line at the points of intersection, and their widths on line. In cases of navigable streams, their width will be ascertained between meander corners…” (Instructions, 1855, p. 466 in Whilte, 1991). p. 10

local, generally minor adjustments using points from the survey notes to the map images to “rubbersheet” the coverages.

The GLO maps can be considered accurate along section boundaries where surveyors

walked, but surveyors did not make observations within the interior of the section. An

exception is where major channels were “meandered,” or mapped by taking bearings and

measuring distances and channel widths (for detail, see White, 1991). The GLO map information includes wetlands, which in many cases show indeterminate boundaries within the interior of sections, line fragments showing the edge of forested or cultivated areas, some woody debris accumulations, and channels.

We digitized available USC&GS charts from paper photocopies of mylars made from

originals, or from versions previously compiled by Bortleson et al. (1980) (see Fig. 5).

Map scales were 1:10,000 or 1:20,000. Minor areas for which I could not find more de-

tailed mapping, primarily in the Samish Island area, are from larger scale maps. We geo-

referenced using latitude and longitude shown on the maps. In one case (Map T-1746) we

shifted the grid of latitude and longitude tics to bring the map into agreement with topo-

graphic features. Information shown on USC&GS maps includes the extent of forest,

tidal wetland, and cultivated areas, and the location of dikes. The USC&GS maps are

generally very accurate.

We digitized an 1897 USACOE map, “Index Map of Skagit River, From its Mouth to the

Town of Sedro, Washington.” The map lacks a coordinate system. We geo-referenced the

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map by finding points, generally railroads and roads, in common with more recent USGS topographic maps. We made local adjustments of the map, based on water and land features. The map shows channels and the major wetland system that existed north of the

Skagit River (the Beaver Marsh-Olympia Marsh system). I also made use of older U.S.

Geological Survey (USGS) topographic maps (Fig. 6).

The historic shoreline was taken from USC&GS mapping. I mapped the landward boundaries of the study area, generally the valley side, using published geologic maps supplemented with interpretations from topographic maps where detailed geologic maps were not available. I also delineated lower river terraces that were identified on geologic

maps.

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Figure 3. Land survey points at which bearing trees were digitized. Where there were no trees available, surveyors built a mound, primarily in tidal areas. Where there were no trees and standing water was too deep in freshwater marshes, no mound was established.

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Figure 4. Year of survey, by township, for GLO cadastral survey maps.

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Figure 5. USC&GS chart sources. Asterisk indicates that map was digitized from

Bortleson et al. (1980).

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Figure 6. Archival topographic maps used in the Samish-Skagit, Stillguamish, and Sno- homish river estuaries. Snohomish (1895) and Mt. Vernon (1911) are 30’ quadrangles; other quadrangles are 15’.

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Approach to Creating “Historic Conditions” Map

Channels. In general, I used USC&GS charts for near-shore channels (i.e., distributary sloughs and blind tidal sloughs), and GLO maps elsewhere. The GLO maps are the earli- est, made 10-15 years prior to widespread snagging and diking. However, in the tidal areas covered by USC&GS maps, the GLO maps are considerably less detailed than the later USC&GS maps. In the Skagit River, I used GLO maps for the South Fork and North

Fork upstream of where they branched into numerous tidal sloughs. In the Snohomish

River, I used GLO maps upstream of Ebey Slough. To map secondary channels (i.e., channels that were not meandered) in the interior of the delta, I made use of topographic maps and aerial photos to assess whether the GLO channels were realistic. Because smaller channels were not meandered, and were measured only where they crossed section lines, the non-meandered channels within sections were taken as, at best, visual estimates by the surveyors, and, at worst, wild guesses. In cases where smaller, non-meandered section-interior channels seemed improbably drawn, I redrew them using topographic maps. Channel-by-channel detail on judgments that were made is provided later in the report.

Freshwater Wetlands. The GLO maps, GLO notes, and ACOE mapping were primary sources for mapping freshwater marshes. I augmented this information with later topographic maps that showed intensively ditched areas; patterns in the soil mapping (USDA

Soil Conservation Service, 1983, 1989; Ness and Ritchins, 1958); flood boundaries in

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FEMA mapping; and elevations on topographic maps. Detail on judgments made in map-

ping individual marshes is provided in discussion of individual maps.

Estuarine Wetlands. Mapping the limit of tidal wetlands was straightforward on the

Snohomish River estuary, because the USC&GS map was made prior to significant dik-

ing. However, map symbols distinguishing freshwater wetlands from saltmarsh, and forested versus scrub-shrub vegetation cover, are subtle or ambiguous on the Snohomish

USC&GS map. To delineate estuarine wetlands in the Snohomish I supplemented the

USC&GS map information with the species and spacing of trees from the GLO notes.

In the Skagit/Samish and Stillaguamish river deltas, there was substantial diking prior to the USC&GS mapping, which made mapping of historic tidal marshes more complicated than for the Snohomish. To make a first approximation of the upper limit of the scrub- shrub estuarine wetland, I took the boundary between forested and cultivated areas mapped by the USC&GS. This line reflected the landward limit of areas that had been cleared for cultivation. I used this line as a first approximation on the assumption that settlers would have preferred to homestead in emergent and scrub-shrub areas instead of clearing the adjacent dense forest. Observations in the GLO notes generally confirm this as the boundary between forest and estuarine wetland (frequently referred to as “tidal prairie”). In the Skagit Flats—the extensive area that drains to the Swinomish Slough and

Padilla Bay—I could not find USC&GS mapping that showed the boundary between forest and cultivated areas, and relied on the GLO maps and notes.

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In all estuarine areas I used the distance of trees to GLO survey points as an indicator of

scrub-shrub wetland compared to the more-closely-spaced trees in the forest. This difference in tree distances generally corresponds with USC&GS chart information where it was available. Finally, modern elevations shown on topographic maps were also used as a secondary, general guide for mapping the upper limit of tidal wetland. Diked lands have subsided since being diked and ditched, and so modern elevations substantially underes- timate historic elevations. However, elevations are useful to the extent to which subsi- dence was relatively uniform, and because they show topographic highs created by natural channel levees. The estimated upper limit of tidal marsh in the study area with respect to modern elevations is roughly 5.5 ft NGVD29 in the Samish-Skagit area and 6 ft

NGVD29 in the Snohomish River (Table 2).

To delineate emergent and scrub-shrub estuarine wetlands I relied primarily on locations where GLO surveyors built mounds because no woody vegetation was nearby. I generally took these points to indicate emergent tidal wetland. This probably overestimates the extent of emergent wetland compared to scrub-shrub wetland. However, I also used as a guide the width of the modern emergent zone (approximately 1 km) in the North Fork and South Fork Skagit deltas. I assumed that the historic extent would have been more than 1 km where the land slope was less (e.g., the Skagit Flats area) or less than 1 km where the land slope greater (e.g. the Samish Flats area). The boundary between the emergent and scrub-shrub tidal wetlands is in all cases generalized and approximate.

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Riverine-Tidal Wetlands. The Skagit and Snohomish rivers both had extensive fresh-

water marshes that appear to have been fed in part by tidal backwater flooding. I mapped

these areas as “riverine tidal.” This usage is contrary to Cowardin et al. (1985), who

while acknowledging that some scientists include adjacent floodplain marshes in the riv-

erine system, advocate confining the riverine wetlands to within channel banks. However,

I follow Hayman et al. (1996) who apply the “riverine tidal” zone to include the flood-

plain wetlands that are flooded in part because of the effects of riverine tidal backwater.

The riverine tidal classification includes forested and scrub-shrub vegetation types; I used

the same approach that is described above to delineate these. This category encompasses

a broad range of conditions. It includes marshes that are flooded primarily by tidal backwater (e.g., the Ebey Island area in the Snohomish River), and those farther from the tidal source which are flooded only partially by this influence, and are also supplied by upland freshwater and ordinary flooding (e.g., Marshland in the Snohomish River).

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Table 2. Elevation limits of tidal marsh in Puget Sound and the Oregon coast: Lower limit of emergent vegetation, boundary between emergent and scrub-shrub transition vegetation; and upper limit of scrub-shrub transition. Elevations are NGVD 1929.

Location Latitude Tidal Marsh

Lower Limit Upper Limit Upper Limit Emergent Emergent Transition Duwamish Estuary 47° 46.3 1.9 ft1 — 7.3 to 8.3 ft2

Ebey Slough, 48° 2.7 — — 6.0 ft3 Snohomish Estuary Skagit Delta 48° 18 0.5 ft5 — 5.1+ ft5

Swinomish 48° 27 1.5 ft4 — 5.5 ft4 Slough/Padilla Bay Bellingham Bay 48° 44.7 3.1 ft6 4.7 ft6 ~6 ft6

Coastal Oregon — 4.6 ft7 5.1 ft7

1 Reported by Blomberg et al. (1988) as 8 ft above MLLW. Seattle, Puget Sound datum (9447130) is NAVD 1988. All Duwamish elevations converted to NGVD using NAVD88 - NGVD29=3.55 ft. 2 Reported by Blomberg et al. (1988) as 2 to 3 ft above MHHW. 3 Upper limit of transition is 1.70 ft above MHW, from U.S. Department of Commerce (NOAA) National Ocean Survey (1975), cited in Frenkel et al. (1981); converted to NGVM using Everett Possesion Sound (9447659). The lower limit of the transition zone is 4.9 ft NGVD. 4 Webber (1989, cited by Swinomish Tribal Planning Dept., 1992) reports salt marsh in the Swinomish Slough occurs between 6 and 10 ft above MLLW. Converted to NGVD from Crescent Harbor datum (9447952), where NGVD is 6.1 ft above MLLW. 5 From Ewing (1983), reported as between 6.6 and 11.2 ft above MLLW. Converted to NGVD using the Crescent Harbor datum. Upper limit is truncated by dikes in Ewing’s study area. 6 From Disraeli and Fonda (1979). They report MLLW is 4.49 ft below NGVD (reported as 4.51 ft at datum 9449211). Maximum is based on their observation that the upper limit of transition is defined by the “maximum high tide;” the maximum measured tide was taken from datum 9449211. 7 From Frenkel et al. (1981), average of three marshes. Lower limit of transition zone av- erages 4.5 ft NGVD.

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Explanation of Historic Conditions Maps

Snohomish River

Estuarine Wetlands. I distinguish two estuarine wetland areas. Emergent wetlands, characterized by witness trees in the GLO surveys, adjoin mudflats at the seaward edge of the estuary. Landward of emergent wetland is a band of scrub-shrub emergent wetlands, which are characterized by wide spacing between trees. Differences in average distance to witness trees, which serves as an index of stand density, delineates the scrub-shrub wetlands and adjacent riverine-tidal forested wetlands. In the scrub-shrub estuarine wetlands, surveyors traveled almost seven times farther on average to find a suitable witness tree (30 m on average in the scrub-shrub area compared to 4.5 m in the forested area;

Table 3). Otherwise, tree cover in the two areas is similar in size and composition (Figs.

7A and 7B) with spruce trees being significantly larger (0.53 m) than other species (0.13 m on average; Figs 8A and 8B). The primary differences between the two are that juniper

(presumably Juniperus scopulorum) in the estuarine scrub-shrub area replaces pine in the riverine-tidal forested area as the dominant species, and spruce is more abundant in the estuarine scrub-shrub area than in the forested tidal wetland (Figs. 7A and B). In both,

spruce have a considerably greater diameter than other species—averaging 0.92 m, compared to 0.15 m for other species, consistent with the common descriptor “spruce marsh.”

When basal area is considered, spruce is overwhelmingly dominant, accounting for 87% of the bearing tree basal area (Fig. 7B).

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Ebey Island Area Riverine-Tidal Forested Wetlands. Adjacent to the estuarine wetlands

are riverine-tidal forested wetlands, with more densely-growing trees. “Rose bushes” were ubiquitous in field descriptions, sometimes “almost impassible.” Willow, “swamp dogwood” (presumably red-osier dogwood, Cornus stolonifera), “buck-bush” were common, and “tall grass” is also present at some points. The Ebey-Island-area forested- riverine-tidal wetlands did not differ greatly from the large floodplain marshes (Marsh- land and French Creek Marsh; see below) in their forest tree cover or in diameter, although trees are somewhat closer together in the forested riverine tidal wetlands (Table

3). As in the scrub-shrub estuarine wetland, spruce accounts for nearly all basal area

(86%, Fig. 7B). Secondary differences include that cedar and hemlock, present in

Marshland and French Creek, are absent from the Ebey-Island area riverine-tidal marsh

(Fig. 7B). Additionally there is less alder in the marsh than in the Marshland or French

Creek marshes; and juniper, yew (presumably Taxus brevifolia), and cascara, not present in the floodplain marshes, are in the Ebey Island-area marsh (Fig. 7B).

Marshland. The “Marshland” area is shown on GLO and USC&GS maps as a vast marsh of about 2,000 ha on the south side of the Snohomish River (Map 2). The USC&GS mapping suggests somewhat larger boundaries to the west than the GLO map, and analysis of the vegetation and topography to the east suggests a smaller boundary than mapped on the GLO map. The eastern margin has a different vegetation pattern suggestive of river bottom; the field notes refer to the area as river bottom subject to overflow from the adjacent Snohomish River, and the area is significantly higher in elevation than the main

Marshland area.

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The marsh is relatively level, mostly below the 5-ft contour on the most recently-published topographic map (the Everett and Snohomish quadrangles, 1953 with 1973 photo- revisions), and slopes upward in the eastern end. The GLO notes indicate that the marsh was subject to overflow “from rains and freshets in the river,” suggesting the Snohomish

River as well as adjacent upland drainage seasonally flooded the area. Morse (in Nesbit et al., 1885) describes it as “fresh-water marsh….” Tidal influence extends upstream beyond the upper end of the marsh, and probably increased the frequency of flooding. I have mapped Marshland as “riverine tidal” for this reason.

Marshland appears to have been a patchwork of scattered-tree-covered areas, willow- hardhack (Spiraea spp.) shrub thickets, and open marsh. Forested areas were relatively sparse, with the average distance from survey points to trees being 13.2 m. Cedar, hemlock, and alder formed somewhat more dense stands, with average distances of 8.2 m; they occurred at more than a quarter (29%) of points. Spruce (Picea sitchensis), and pine

(presumably Pinus contorta) were more scattered, averaging 18.1 m from survey points.

Pine was the most common tree, and except for one point where there was also a spruce, it tended to be the only species present. The open spacing of the pine and spruce is consistent with the frequent descriptive references to hardhack-willow thickets with scattered pines. This latter scrub/forest vegetation of hardhack-willow shrub with scattered pines or spruces accounted for another two-fifths (38%) of points. The remaining two-fifths (43%) of points had no trees near enough to serve as witness trees; most of these locations are described as willow-hardhack or as “open.”

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The spruce, cedar (Thuja plicata), and hemlock (Tsuga heterophylla), which accounted for 13%, 9% and 3% of trees in Marshland, respectively (Fig. 7C), were relatively large, averaging 0.60 m, 0.91 m, and 0.71 m, respectively (Fig. 8C). Smaller were alder (Alnus rubra), accounting for 28% of total trees, 0.26 m in diameter, and scrub pine, the dominant tree (44% of trees), averaging 0.19 m.

Much of Marshland was flooded with a few feet of water at the time of the survey in Feb- ruary 1871. There were 23 survey points. Of these, field notes indicate the depth of water at 11, where depth averaged 0.67 m, and at an additional two points the water was too deep for access. Five additional points were too wet to build a mound, and three more points were described as “swamp.” Thus, between 13 and 21 of 23 points had standing water. The water at three points was greater than a meter in depth, and the two points too deep to access were presumably deeper, meaning that at least five points were deeper than 1 m. Most points were described as “subject to overflow” to depths greater than the water that was present at the time of the survey. At eleven points the surveyors provide quantitative estimates of seasonal flood depth which was on average 0.67 m. The published map shows “subject to overflow 2 to 6 ft” (0.6 to 1.8 m).

The extent of summer inundation is not known directly, but might be suggested by the widespread absence of trees and the prevalence of willows. Additionally, the soils in about one-fifth of the area of Marshland are mapped as the Mukilteo Muck soil series

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(Debose and Klungland, 1983), organic soils developed under sedges and rushes. Earlier soils mapping (Mangum, 1909) shows most of the Marshland area as “muck and peat.”

Marshland is designated “cranberry swamp” on the GLO map. Cranberries are mentioned at one location in the field notes. It is interesting to note that in the Fraser River delta, a reconstruction of historic vegetation by North and Tevarsham (1984) includes “cranberry swamp” as a map unit. Similar to the Snohomish’s Marshland, the Fraser delta area has

“’some hardhack and pine;’ described in one instance as ‘low pine brush mostly dead- ened by fire with great abundance of cranberries’” [North and Teversham (1984) identify the pine as Pinus contorta]. North and Tevarsham also indicate that ethnobotanic litera- ture suggests it is likely that Indians cultivated the Fraser cranberry swamp.

French Creek Marsh. The French Creek marsh is shown as 1,400 ha on GLO maps and is on the north valley side upstream of the town of Snohomish (Map 2). The marsh appears to have been more densely vegetated than Marshland. All survey points (14 points) had trees close enough to serve as witness trees, and the average distance to trees was 6.3 m. Pine, spruce, and crabapple were the dominant trees; alder, cedar, and willow were secondary (Fig. 7D). All trees were similar in size except for crabapples, which were smaller in diameter. Similar to conditions in Marshland, pines tended to serve as witness trees alone, without other trees, and were somewhat more widely spaced, averaging 9.4 m from survey points compared to 5.5 m for other trees. As in Marshland, pine-covered areas appear to be sparser than tree cover in other parts of the marsh.

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According to Morse (Northern Star Newspaper, April 4, 1877), the marsh had two identi- fiable portions. A forested band of trees divided the marsh into an upper and lower half:

“It is nearly cut in half by a swath of spruce and cedar timber...The part below this belt, called the lower marsh, ...is splendid pasture land in the summer and fall. [It] is overflowed by freshets in winter and spring...The upper marsh is beaver meadow, covered with grass, hardhack and tea brush [(Ledum groenlandicum) with] no timber of any size.”

Witness tree data do not contradict Morse’s description; the distance to trees is greater in

the upper part of the marsh, but there are too few points to make a comparison on that

basis. However, the descriptions of water depth and beaver dams do contradict Morse’s

description as only the upper part being “beaver marsh.” Surveyors describe French

Creek marsh as inundated by water on account of beaver dams, except for two points in

the very lowest (westerly) end. Soils in about one-third of the marsh (31%) are mapped as

Mukilteo Muck (Debose and Klungland, 1983), which as indicated previously is a very

deep soil formed “in organic material derived dominantly from sedges.”

The French Creek marsh was surveyed in late July and August of 1866. July and August

is in the region’s dry season, and so the recorded water depths can reasonably be taken as

summer, minimum-water-level conditions. Several descriptions in summer 1866 indicate

the area is flooded by water impounded by beaver dams. For example, descriptions of the

area include: “…swampy and generally overflowed to the depth of 12 inches in conse-

quence of beaver dams…” on what was termed “Deep Creek,” which is presumably

French Creek. Elsewhere the area is described as “…mostly overflowed now to the depth

of from 4 to 8 inches…liable to annual inundation of 36 inches…” and “…land in the

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valley mostly overflowed to the depth of 4 inches….” Owing to its location, it seems

likely that the French Creek marsh was less affected by Snohomish River floodwaters

than it was by impoundment of upland runoff by beaver dams. The wetland is shown on

Map 2 as palustrine scrub-shrub wetland. Overall, based on the GLO notes, it appears the

marsh experienced shallow summer flooding (less than 0.3 m) caused by beaver dams, and periodic winter inundation of about 1 m. The exact extent is not clear, but most of the marsh appears to have been flooded by beaver dams in the summer.

Riparian and Floodplain Vegetation. Most of the mainstem as far upstream as Thomas’

Eddy at river kilometer 27 is tidally influenced. In tidal-freshwater riparian forest, alder was the dominant tree, making up nearly half (46%) of trees (Fig. 9B). Broad-leafed deciduous trees account for 70% of trees. Sample sizes are smaller in the estuarine tidal riparian forest. The limited sample includes juniper, alder, crabapple, and spruce in de- scending order of importance (Fig. 9A). Deciduous species account for 50% of trees. In the upstream non-tidal riparian forest, sample size is again small. Willow was the dominant witness tree (40% of the total), and deciduous trees accounted for 86% of trees (Fig.

9C). Bearing trees were larger in diameter and more closely spaced in the tidal-freshwater riparian forests than in the estuarine riparian forest. The average diameter of bearing trees was 0.28 m and 0.44 m respectively (Fig. 10), and the average distance to bearing trees was 17.9 m and 10.4 m.

Conifers were slightly more abundant away from the river than immediately adjacent to it, but were still not dominant, comprising 37% of trees on the floodplain, compared to

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50% in estuarine riparian, 70% in tidal-freshwater riparian, and 86% in freshwater riparian forests (Fig. 9D). Alder is less abundant on the floodplain than in the immediately streamside area, accounting for 18% of trees. Instead, maple and vine maple were abundant. The overall average diameter of trees was 0.41 m. The largest were cedar (0.87 m), cottonwood (0.73 m), spruce (0.52 m) and maple (0.48 m; Fig. 10).

Table 3. Selected characteristics of trees described in GLO field notes for major marsh areas in the Snohomish river valley.

Wetland Area Number Percent Number Average Average (ha) of with of Trees Tree Distance Survey Trees Diameter to Trees Points French Creek 1,440 14 100% 34 0.17 m 6.7 m Marsh Marshland 1,920 23 57% 32 0.34 m 13.2 m

Riverine-Tidal 3,000 18 94% 42 0.24 m 4.5 m Forested Estuarine 1,020 8 100% 18 0.24 m 33.0 m Scrub-Shrub

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Frequency Basal Area

Estuarine C'APPLE ALDER YEW 1% ALDER Scrub- 5% <1% 1% YEW JUNIPER Shrub 5% C'APPLE 5% 10% FIR Wetland 7% (n=18) SPRUCE 25%

JUNIPER SPRUCE 44% FIR 87% 15%

B. WILLOW C'APPLE Forested YEW 1% <1% <1% CASCARA Riverine CASCARA 8% JUNIPER Tidal <1% 1% SPRUCE PINE Wetland FIR 7% C'APPLE 12% (n=42) WILLOW 5% 3% 12% FIR YEW 3% 19%

JUNIPER 3% PINE SPRUCE 39% 86%

Figure 7. Species abundance by frequency and basal area, identified in GLO notes in four

marsh areas in the Snohomish River valley: (A.) Estuarine scrub-shrub wetland; (B.) For- ested riverine-tidal wetland (continued on following page).

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Frequency Basal Area

C. C'APPLE “Marshland” <1% PINE ALDER Wetland 10% ALDER 28% (n=32) PINE 28% 44% SPRUCE 17% CEDAR SPRUCE 50% 13% C'APPLE HEMLOCK 3% 9% CEDAR HEMLOCK 9% 3%

D. WILLOW French WILLOW 9% Creek ALDER 3% Marsh PINE 12% PINE ALDER 21% 16% 14% (n=34) C'APPLE 3% CEDAR CEDAR 10% 9% C'APPLE SPRUCE 25% 24% SPRUCE B'BERRY 51% 2% B'BERRY 2%

Figure 7 (continued). Species abundance by frequency and basal area, identified in GLO notes in four marsh areas in the Snohomish River valley: (C.) Marshland scrub-shrub riverine-tidal wetland; (D.) French Creek Marsh.

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A. B. 1.4 1.4 Estuarine 1.2 1.2 Riverine-Tidal Scrub-Shrub n=4 Forested Wetland 1 1

0.8 0.8 n=5

0.6 0.6 n=3 0.4 0.4 n=8 n=16 n=5 n=1 n=6 n=3 n=1 n=2 0.2 n=1 0.2 n=1

0 0

C. D. 1.4 1.4 n=3 1.2 Marshland 1.2 French Creek Marsh 1 1

0.8 n=4 n=1 0.8

0.6 0.6 n=14 n=9 0.4 0.4 n=3 n=4 n=8 n=2 n=7 n=8 0.2 n=1 0.2 n=1

0 0

Figure 8. Diameter of trees, from GLO field notes, in four marsh areas of the Snohomish

River. Sample is the same as in Figure 5.

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Frequency Basal Area

A. JUNIPER Estuarine 12% Riparian (n=10) ALDER JUNIPER 30% 40% SPRUCE ALDER

28% 59% C'APPLE

20% C'APPLE SPRUCE 1% 10%

Tidal Freshwater FIR JUNIPER JUNIPER YEW FIR YEW Riparian 1% 1% <1% CEDAR 4% (n=141) <1% 1% 11% HEMLOCK ALDER WILLOW 2% ALDER CEDAR 23% 1% SPRUCE 42% 45% 10% MAPLE 8% C'APPLE V'MAPLE SPRUCE <1% 7% 18% V'MAPLE WILLOW HEMLOCK C'APPLE 4% MAPLE 6% 1% 8% 7%

Figure 9. Species abundance, by frequency and basal area, of riparian and floodplain trees in GLO field notes in the Snohomish River valley: (A.) Estuarine riparian; (B.) Tidal- freshwater riparian (continued on following page).

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Frequency Basal Area C. CEDAR WILLOW Freshwater 7% ALDER Riparian SPRUCE 3% 3% V'MAPLE 7% 1% (n=15) ALDER CEDAR C'WOOD 13% 20% 13% MAPLE WILLOW 35% 40% SPRUCE 28% MAPLE 7% C'WOOD V' MAPLE 10% 13%

D. YEW YEW WILLOW HEMLOCK 2% <1% 1% 5% V' MAPLE Forested CEDAR WILLOW ALDER ALDER 11% 5% 1% Floodplain 18% 11% (n=129) CEDAR MAPLE 10% SPRUCE 44% 19% V' MAPLE C'WOOD 12% 9% C'APPLE MAPLE SPRUCE OTHER <1% DECID 10% 22% OTHER 7% C'APPLE HEMLOCK C'WOOD 1% 7% 4% 1%

Figure 9 (continued). Species abundance, by frequency and basal area, of riparian and floodplain trees in GLO field notes in the Snohomish River valley: (C.) Freshwater (non- tidal) riparian; (D.) Non-wetland floodplain areas.

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B. A. 1.6 1.6 1.4 Estuarine 1.4 Tidal-Fresh Riparian n=3 n=10 1.2 Riparian 1.2 n=3 n=15 1 1 n=61 0.8 0.8

0.6 n=1 0.6 n=6 n=3 n=16 0.4 0.4 n=10 n=1 n=2 n=9 n=4 n=1 0.2 n=2 0.2 n=6 0 0

C. D. 1.6 1.6 1.4 Freshwater 1.4 Forested Floodplain

Riparian 1.2 n=2 1.2 n=1 n=3 n=5 1 n=1 1 n=1 n=21 0.8 0.8 n=10 0.6 n=2 0.6 n=3 n=11 0.4 0.4 n=15 n=3 n=2 n=6 0.2 n=2 0.2 n=8 0 0

Figure 10. Diameter of trees, from GLO field notes, in the Snohomish River riparian forest and the non-wetland floodplain.

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Stillaguamish River

Estuarine Wetlands and Channels. Primary information used to delineate the upper limit of estuarine wetland was the boundary between forested and cultivated land shown on the

USC&GS map. The GLO notes confirm the coincidence of this boundary with that between wetland and forest. The presence or absence of witness trees was used to create a boundary between emergent and scrub-shrub vegetation, but the boundary is broadly generalized because of a small number of survey points. The modern extent of emergent wetland in the South Fork Skagit River marshes was also used as a guide; there, emergent vegetation extends roughly 1 km up-delta.

Blind tidal channels were not mapped in detail on GLO maps or USC&GS maps, in the latter case because diking had occurred prior to the mapping. A large blind-tidal network on the Stillaguamish delta was extended beyond the GLO or USC&GS maps using traces of channels visible on 1933 1:12,000-scale aerial photographs. The extent of USC&GS mapping of this channel network is roughly to the boundary between the emergent and scrub-shrub vegetation (where a dike had been built prior to 1886). Hancock Slough (the slough marking the north boundary of the Stillaguamish area) was not shown on GLO mapping, and had been ditched by the 1886 USC&GS mapping. I showed the part of the slough that had not been diked, although even that part of the slough, from appearances, had almost certainly been straightened.

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Freshwater Wetlands. The wetland that is 1-2 km up-valley from Florence (in Sections

28, 29, 32, and 33) is larger on Map 1 than shown on the GLO map. The wetland area shown on the map has largely indeterminate boundaries, meaning that the surveyors did not interpolate beyond the section lines into the section interiors (Fig. 11). I drew the wetland on Map 1 near Norman and north of Silvana by connecting two wetlands with indeterminate boundaries on the GLO map. The third wetland, between Stanwood and

East Stanwood, is based on connecting two wetlands shown on the GLO map (Fig. 10).

Raft Jams. Three raft jams are shown on the map. The lowermost jam blocked the upper end of Hatt’s (now “Hat”) Slough. The exact location of the jam is not known. A second jam was described by pioneers (for summary, see Eide, 1996; Interstate Publishing Com- pany, 1908), and the location on Map 1 is a best estimate from those sources. In summer

1998, large numbers of waterlogged and well-weathered pieces of wood debris were ob- served on the riverbed at this location. Less is known about a third jam (see Eide, 1996) at or immediately upstream of the upper limit of tidal backwater influence (backwater extends to roughly the reconnection of Cook Slough and the mainstem).

Wetlands and Beaches on Fidalgo Island. The USC&GS map shows the main area of coastal-fringing lowland in Livingston Bay (in Section 29, south of SR 532) as forested.

However, the GLO notes indicate marsh area (including “cranberry marsh”), and soils mapping (Ness and Ritchins, 1958) indicates soils formed under marsh vegetation. The soils mapping also indicates beach-soil areas seaward of the marsh, and USC&GS map indicates grassland, consistent with an interpretation of beach dunes. Other areas along

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Livingston Bay were interpreted using similar information. The small stringer of “forested floodplain” north of Juniper Beach and west of Davis Slough was described as a line of cedars in the GLO notes, and is shown in soils mapping (Ness and Ritchins,

1958).

Table 4. Selected characteristics of vegetation in several marsh areas in the Stillaguamish river estuary. PSW = Palustrine scrub-shrub wetland; RTSW = Riverine tidal scrub-shrub wetland.

Wetland Wetland Number Percent Number Average Average Area (ha) of Survey of Points of Trees Diameter Distance Points with in of Trees to Trees Trees Sample (m) (m) PSW near 200 2 50 2 0.32 5.0 Norman RTSW near 160 3 33 2 0.36 10.7 Florence RTSW near 150 2 100 6 0.18 14.8 Stanwood Estuarine 1,120 23 0 0 -- -- Emergent Estuarine 600 6 17 2 0.46 79.7 Scrub-Shrub

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Skagit-Samish River Delta

Channels. On the Skagit-Samish delta, channels for near-shore areas (i.e., roughly coin-

cident with the extent of estuarine marsh) were taken from USC&GS charts. Although

USC&GS charts were made 10-20 years after GLO plats, they are considerably more ac-

curate and detailed than GLO maps, and while diking had begun two decades prior to the

USC&GS mapping, diking did not appear to have significantly changed mainstem and

distributary channels. The Skagit forks and mainstem are mapped from the GLO map.

Interior sloughs and channels on Map 1 are from a variety of sources. Sloughs on Fir Is-

land are from the USC&GS map. In the northern, Samish-River area, channels are from

the GLO map, except for the extension of Joe Leary Slough into Olympia Marsh, which

is from the 1897 ACOE map. In the Skagit Flats area (i.e., west of Avon Bend, in the

Beaver Marsh area), the GLO channels were taken as a guide, but in some places in the

interior of sections they appeared topographically implausible. In those cases I modified

channel locations to take into account topography and channel locations shown on 1911

and 1941 topographic maps for the area.

The GLO map shows the location of a large raft-jam complex in the Skagit River near

Mount Vernon, which is included in the historic coverage. This jam had been present for at least a century. Settlers’ accounts indicated that trees 2-3 ft in diameter grew on its sur- face (Interstate Publishing Company, 1906). The jam routed floodwaters into Beaver

Marsh and Olympia Marsh (e.g., U. S. War Department, Annual Reports of the Chief of p. 39

Engineers [ARCE] 1881, 1898). The 1897 map by the Army Corps of Engineers also

shows debris jams and some individual snags. This map information is a snapshot in

time, taken after the raft jam had been removed, and after a decade-and-a-half of snagging on the river. Wood debris is included in the GIS coverage as a separate type.

Beaver Marsh. “Beaver Marsh” is a complex of marshes in the Skagit Flats. For this analysis, the main Beaver Marsh is taken to refer to the southern portion of the marsh, which is distinct morphologically from the north part. The vegetation is almost every- where described as hardhack, willows, flags and tules. In some cases willow and hardhack are in “dense thickets,” and in a few locations described as “beaver marsh covered with hardhack and willow.” The abundance of willow (Fig. 12C) is consistent with an abundance of beaver ponds.

The General Land Office surveyed Beaver Marsh in August 1872. They made relatively few observations on water depth, or the source of water. In the southwest part of the marsh, an observation is made that the “swamp [is] subject to inundation during the winter and most of the year 1-3 feet deep.” The marsh is notable for the lack of topographic relief. The present-day elevation is entirely below the 5-ft contour. It appears likely that the marsh was at least in part created by tidal backwater; GLO field notes imply that the

“tide bottom” inter-fingers with the western portion of the marsh. The area is fed by freshwater from creeks flowing in several relict mainstem river channels in the “upper

Beaver Marsh” area.

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“Upper Beaver Marsh,” the complex of marshes that feed Beaver Marsh, and that drain

directly to Padilla Bay and the Swinomish Slough, is characterized by ridge-and-swale topography characteristic of relict river channels. On topographic maps and aerial photos, the channels appear large enough to have been relict Skagit River channels. This infer- ence is consistent with an Army Engineer’s description of the area based on an 1872 field examination:

“While making an examination of the low lands lying between the Skagit and Samish, in 1872, I saw indications that the former at one time flowed into Padilla Bay, 12 miles north of the present mouth of Steamboat Slough; the old channel being easily traced, traversed by numerous beaver dams, doubtless the principle cause of the diversion of the river into its present course” (ARCE, 1881).

On this basis I interpret the marshes in the “Upper Beaver Marsh” to be formed primarily by beaver dams exploiting topography in relict mainstem channels. The vegetation was less shrubby than in the main area of Beaver Marsh (Figs. 13C and 13D; note difference in scale), and more diverse in composition (Figs. 12C and 12D).

Olympia Marsh. Olympia Marsh includes areas that were dominantly forested or scrub- shrub. Boundaries between these two vegetation types were made on the basis of: (1) a difference in pattern shown on the ACOE map in forested areas; (2) descriptions in the

GLO notes; and (3) secondarily the presence of hemlock, which is less tolerant of flooding than other tree species in the area. These boundaries are broadly generalized.

Most sample points (15 of 24) in the scrub-shrub portion of Olympia Marsh lacked any witness trees. The remaining areas were dominated by willow and spruce (Fig. 12A). As

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in estuarine scrub-shrub wetlands, spruce were the only large-diameter tree (Fig. 13A)

and account for the majority of basal area (Fig. 12A). In the dominantly forested part of

Olympia Marsh, 2 of 14 locations lacked trees. The most common trees were alder and secondarily spruce and hemlock (Fig. 12B). Hemlock and fir were largest in diameter

(Fig. 13B). Figure 11 shows the primary sources of information used to map Olympia

Marsh and other wetlands on the Skagit-Samish delta. The ACOE map and GLO plats and field notes were supplemented with FEMA flood maps to confirm marsh boundaries.

South Fork Skagit Riverine-Tidal Wetlands (near Cedardale). A system of freshwater wetlands were present to the east of the South Fork Skagit River (Map 1), in Map 1 shown as 1,370 ha. The wetlands near the present-day village of Cedardale are primarily an alder-willow swamp, similar to the tree cover in Beaver Marsh (Fig. 12E). Because of the proximity to tidal source and the relative elevation, the wetland is mapped as riverine- tidal. The GLO notes do not include sufficient information for estimating the depth of winter inundation. More than other wetlands on the Skagit delta, the boundaries of this wetland complex are extrapolated (Fig. 11), because GLO mapping did not extend beyond the section lines and shows indeterminate boundaries to wetland areas.

Wetland North of Bow. The GLO map shows a wetland immediately north of the present-day town of Bow (Fig. 11). On the basis of the GLO field notes, the marsh is mapped somewhat larger (189 ha) than on the GLO map, on which the marsh has indeterminate boundaries. The GLO notes describe the area as a “spruce and crabapple swamp covered with water to the depth of one to two feet” on March 25, 1872.

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Wetland South of Bow. The GLO map shows a wetland approximately 1-2 km southeast

of the town of Bow. The wetland on Map 1 (54 ha) is larger than shown on the GLO

map, based on the size of wetlands shown on subsequent topographic maps. The GLO

notes describe the area as a “swamp covered with hardhack brush.”

Fir Island Wetlands. The GLO mapping shows several wetlands on Fir Island having

indeterminate boundaries. Making use of field notes and elevations on topographic maps,

these areas have been extended and combined into two forested wetlands that follow

broad swales or channels that are presumed to be tidally-influenced (Map 1). The tree

cover is more closely spaced than the nearby scrub-shrub wetlands near Cedardale; the average distance to trees from survey points was 5.7 m. Alder and spruce together account for four-fifths of the tree sample (Fig. 12F). Similar to the wetlands near Cedardale, it is assumed that these wetlands are primarily inundated during winter floods, and are influenced by tidal backwater effects.

Estuarine Wetands. Throughout the Skagit-Samish delta, estuarine wetlands had already been diked by the time USC&GS maps were made (see Fig. 5 for dates). Estuarine wetlands were mapped using: (1) the boundary between forested and cultivated areas on the

USC&GS charts, as previously described, and (2) the presence and spacing of GLO witness trees. The average distance to bearing trees in the estuarine scrub-shrub wetland was

35.2 m, considerably more than adjacent riverine-tidal wetlands or floodplain forest (Fig.

6). In the Swinomish Slough and Padilla Bay area, USC&GS charts were not found

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showing the edge of forest, and mapping was exclusively from the GLO maps and field notes.

Riparian and Floodplain Forests. Alder is a major component of all forests, which are diverse (Figs. 14 and 15). Except for estuarine scrub-shrub riparian forests and forested terraces, conifers are less abundant than deciduous trees (Fig. 14), although conifers are larger (Fig. 15), particularly spruce in the estuarine riparian areas, and spruce and cedar in freshwater forests. Flood-intolerant hemlock is an important forest constituent only on the floodplain terrace (Fig. 14F).

Table 5. Selected characteristics of vegetation in several wetlands on the Skagit-Samish delta, and for comparison, characteristics of the non-wetland floodplain.

Wetland Area Survey Percent Number Average Average (ha) Points with of Trees Diameter Distance Trees (m) (m) Upper Beaver 1,660 18 100% 45 0.33 9.7 Marsh Lower Beaver 1,370 12 100% 28 0.17 16.5 Marsh Olympia Marsh 3,580 38 55% 51 0.26 4.7 (scrub-shrub) (2,360) (24) (38%) (23) (0.29) (4.6) (forested) (1,220) (14) (86%) (28) (0.24) (4.8) Riverine-Tidal 1,370 11 100% 26 0.21 12.9 Scrub-Shrub near Cedardale Fir Island Riverine- 790 15 100% 15 0.28 5.7 Tidal Forested Estuarine Scrub- 2,820 20 100% 45 0.38 35.2 Shrub Non-Wetland 13,020 127 100% 340 0.44 8.2 Forested Floodplain

p. 44

Figure 11. Map sources for wetlands in the Skagit-Samish and Stillaguamish estuaries.

p. 45

A. Frequency Basal Area ALDER HEMLOCK HEMLOCK 4% Olympia 6% 10% Marsh ALDER WILLOW N=16 13% SPRUCE 16% 25% WILLOW C'WOOD 43% 15% C'WOOD SPRUCE 13% 55% B. Olympia FIR FIR WILLOW 6% ALDER Marsh 13% ALDER 1% Forested HEMLOCK 21% 19% 30% N=28 CEDAR HEMLOCK SPRUCE

10% 44% 14% SPRUCE WILLOW 19% CEDAR 6% BIRCH 4% C. 10% SPRUCE Beaver B'BERRY B'BERRY SPRUCE 4% 7% 4% 11% Marsh MAPLE

N=28 4% MAPLE C'APPLE 6% ALDER ALDER 4% 39% 39% C'APPLE 1% WILLOW WILLOW 42% 37%

Figure 12. Distribution of tree species in six freshwater wetlands on the Skagit-Samish delta: (A.) Olympia Marsh; (B.) Forested Olympia Marsh; (C.) Beaver Marsh.

p. 46

Frequency Basal Area

D. OTHER WHITE FIR ALDER CON. 6% 9% WILLOW Upper 7% 9% ALDER Beaver CEDAR MAPLE 20% Marsh 13% 2% N=45 CEDAR SPRUCE WILLOW 40% 20% 32% SPRUCE 33% V' MAPLE <1% V' MAPLE

4% MAPLE C'APPLE 2% 2% E. ALDER ALDER Fir Island SPRUCE 21% Riverine 40% 40% WILLOW Tidal SPRUCE 11% Forested 40% Wetland WILLOW N=15 C'APPLE 13% C'APPLE 7% 1%

HEMLOCK SPRUCE 4% HEMLOCK F. 8% 3% Riverine Tidal SPRUCE 13% Scrub- ALDER WILLOW ALDER 66% Shrub 23% Wetland 66% WILLOW N=26 29%

Figure 12 (continued). Distribution of tree species in six main freshwater wetlands on the

Skagit-Samish delta: (D.) Upper Beaver Marsh; (E.) Fir Island Riverine Tidal Forested

Wetland; (F.) Scrub-Shrub Riverine Tidal Wetland.

p. 47

A. 1.4 B. 1.4 1.2 Olympia Marsh 1.2 Olympia Marsh Forested Scrub-Shrub 1 1 0.8 n=4 0.8 n=6 0.6 0.6 n=1 n=2 n=2 n=5 0.4 n=5 0.4 n=9 n=3 n=2 n=3 0.2 n=1 0.2 0 0

C. D. 1.4 1.4 n=6 Upper 1.2 Beaver Marsh 1.2 n=9 Beaver Marsh 1 1 0.8 0.8 n=3 0.6 0.6 n=1 n=11 n=9 n=14 n=2 0.4 n=1 n=12 0.4 n=1 0.2 n=2 n=1 n=1 0.2

0 0

E. F. 1.4 1.4

1.2 Riverine-Tidal 1.2 Fir Island Riverine-Tidal 1 Scrub-Shrub 1 n=6 Forested 0.8 0.8

0.6 0.6 n=1 n=6 n=3 0.4 0.4 n=2 n=10 n=1 0.2 0.2 n=1

0 0

Figure 13. Diameters of tree species in six major freshwater marshes on the Skagit-Sam- ish delta.

p. 48

A. Frequency Basal Area WILLOW C'APPLE Estuarine ALDER 1% <1% Scrub- 4% MAPLE HEMLOCK JUNIPER 4% Shrub 2% JUNIPER ALDER WILLOW 6% C'WOOD 17% 17% FIR <1% Wetland 5% HEMLOCK FIR 2% 9% BIRCH N=45 10% C'APPLE 5% 3% MAPLE CEDAR CEDAR 2% 3% 5% SPRUCE C'WOOD SPRUCE 33% BIRCH 2% 68% 2%

B. CEDAR JUNIPER JUNIPER 3% 2% 3% Estuarine Riparian CEDAR ALDER ALDER 21% 22% N=63 SPRUCE 34% C'WOOD 24% WILLOW 2% 8% SPRUCE MAPLE MAPLE 31% C'APPLE WILLOW 13% 2% <1% 31% C'APPLE C'WOOD C. 2% 2%

Tidal SPRUCE CEDAR Freshwater 6% ALDER OTHER V'MAPLE 9% Riparian 5% <1% 1% C'WOOD N=54 4% C'WOOD 7% SPRUCE ALDER 4% MAPLE 1% 60%

C'APPLE CEDAR 8% 87% WILLOW 8%

Figure 14. Frequency of trees in GLO notes from the Skagit-Samish delta in: (A) Estua- rine scrub-shrub wetland; (B) Estuarine riparian forest; (C) Tidal-freshwater riparian.

p. 49

Frequency Basal Area FIR C'APPLE HEMLOCK WILLOW D. 5% HEMLOCK <1% MAPLE 5% 2% 1% <1% Freshwater FIR C'WOOD ALDER ALDER 6% 4% Riparian 14% CEDAR 31% BIRCH N=83 13% <1% V'MAPLE CEDAR SPRUCE <1% 13% 40% WILLOW CHERRY 15% SPRUCE CHERRY 1% 33% <1% V'MAPLE C'APPLE 2% 2% BIRCH C'WOOD MAPLE 4% 8% 1% E. FIR YEW W'FIR HEMLOCK WILLOW HEMLOCK 1% <1% 1% W'FIR 4% 2% Forested 9% 1% C'APPLE ALDER 1% Floodplain 13% CEDAR ALDER MAPLE N=340 32% 2% 15% CEDAR 37% OTHER SPRUCE WILLOW <1% ELDER SPRUCE 17% 8% <1% 40% C'APPLE HAZEL 4% <1% MAPLE 5% B'BERRY V'MAPLE C'WOOD F. 2% BIRCH 1% 2% 3% Forested FIR FIR Terrace 3% 3% ALDER N=35 ALDER 7% 7% HEMLOCK WILLOW HEMLOCK WILLOW 70% <1% 70% <1% MAPLE <1% MAPLE CEDAR CEDAR <1% 18% SPRUCE 18% 2% SPRUCE 2% Figure 14 (continued). Frequency of trees in GLO notes from the Skagit-Samish delta in:

(D) Freshwater riparian; (E) Forested floodplain; and (F) Forested terrace.

p. 50

A. 2 B. 2 Estuarine Scrub-Shrub Estuarine Riparian 1.5 1.5 n=13 n=1 n=4 1 1

n=1 n=19 n=2 n=1 n=17 n=7 n=1 n=1 n=20 0.5 n=9 0.5 n=1 n=1 n=1 n=2 n=1

0 0

C. D. 2 2 n=11 Skagit Tidal Riparian Freshwater Riparian n=11 1.5 1.5 n=4 n=2 n=4

n=1 1 1 n=25 n=59 n=7 n=17 n=1 n=26 0.5 n=6 0.5 n=2 n=12 n=3 n=1 n=2 n=1 n=2 n=1

0 0

E. F. 2 2 n=58 Floodplain Forested Terrace n=50 Forest 1.5 1.5 n=3 n=108 n=31 1 n=16 1 n=4 n=17 n=28 n=2 n=4 n=13 0.5 n=9 0.5 n=1 n=7 n=4 n=11 n=7 n=1 n=1 0 0

Figure 15. Diameter of trees in the estuarine scrub-shrub wetland area, and in riparian and floodplain forests on the Skagit-Samish delta.

p. 51

Historic Area of Wetlands and Channels

Areal Extent of Wetlands

The study areas, excluding channels, were historically more than half wetland. In the

Snohomish valley, which includes a portion upstream of tidal influence, wetlands covered nearly two-thirds (62%) of the total land area. In the Skagit-Samish delta and Stil- laguamish estuary, both of which also include substantial land area upstream of tidal influence, 54% and 53% respectively was wetland (Table 6 and Fig. 15).

Table 6. Land areas in ~1860 for the three study areas.

Land Type Skagit-Samish Stillaguamish Snohomish (ha) (ha) (ha) Estuarine Emergent 5,620 1,120 440 Wetland Scrub-Shrub 2,820 600 1,020

Riverine-Tidal Scrub-Shrub 2,780 300 1,800 Wetland Forested 790 0 3,000

Palustrine Scrub-Shrub 4,110 290 1,440 Wetland Forested 1,620 0 20

Non Wetland Floodplain 13,020 2,010 4,290

Terrace 1,920 0 380

ALL WETLANDS 17,730 2,310 7,720 ALL LAND 32,670 4,330 12,380

p. 52

The Skagit-Samish delta and Snohomish River valley are also both notable for the extent

of freshwater marsh, which exceeds the area of estuarine marsh in both cases. On the

Skagit-Samish delta, freshwater marsh was 1.1 times the extent of estuarine marsh (Table

6 and Fig. 15). In the Snohomish valley, freshwater wetland was 4.2 times the area of estuarine marsh. By contrast, the Stillaguamish River estuary has only one-third as much freshwater wetland as it has estuarine marsh. The geologic histories and geomorphic setting of the three areas explain at least some of this difference. Erosion associated with continental ice sheets created the Snohomish River valley (Booth, 1994), and it is broad and gentle in slope. By contrast, the Stillaguamish River has cut its valley through glacial sediments since the last glaciation, and it is narrower and steeper than the Snohomish valley. The Skagit-Samish delta, which has an intermediate extent of freshwater wetland,

is a third geomorphic setting. Like the Snohomish valley, it is also low-gradient and

broad, but less confined.

Channel Area

The channel network is broken into several channel types. I defined mainstem channels as

the main Samish, Skagit, Stillaguamish, and Snohomish rivers upstream of their branch-

ing into distributary channels. Blind tidal channels are primarily created by and drain

tidally- or flood-introduced water (Simenstad, 1983) and are characterized in map-view

by a narrowing with increasing distance from the tidal source. Blind tidal channels also

fed by significant amounts of freshwater from distributaries are called distributary-blind

tidal (Table 7). Tidal channels having primarily tidal flows (i.e., little freshwater flow), p. 53

typically between the bays in the study area, are called connecting channels. Other channel types are distributary, tributary, and floodplain slough.

The areas in Table 7 are primarily totals of Arc/Info polygons. Additional channel areas were estimated from channels that are shown on the original maps as lines (and appear as arcs instead of polygons in Arc/Info) by multiplying their length by an assumed average channel width of 5 m. These additional areas are identified in Table 7. They account for about 2% of the area in the Skagit-Samish, and 1% in the Stillaguamish.

It is also necessary to estimate the area of blind tidal channels, because archival maps used to create the channel coverages generally show only larger blind channels. Estimates were extrapolated from field measurements from Fir Island in the Skagit River delta

(Collins 1998). The Skagit estimates were derived by relating measured channel area for several networks to the outlet channel width of each. I used a power-law regression between these measurements to extrapolate for all tidal networks, based on the width of their outlet channel as mapped from large-scale aerial photographs. Regression-predicted network areas were totaled and channel area was determined as a percentage of marsh area. This percentage varied in different parts of the Skagit delta (Collins 1998, Table 3).

For this extrapolation, I used an average of 6% of marsh area in the estuarine-emergent wetland, and 4% in estuarine scrub-shrub wetland. No field data is available from riverine-tidal areas, where I used 2%, based on the apparent lower density of relict channels visible on early (early 1930s) aerial photographs. These percentages were applied to the marsh areas in Table 6; the measured blind-tidal and distributary/blind-tidal areas in Ta-

p. 54

ble 7 were subtracted from the result to give the estimated “unmapped blind tidal chan-

nel” area in Table 7. I excluded from the calculations the land area of Marshland, the riv-

erine-tidal scrub-shrub marsh in the Snohomish valley, because few relict tidal channels

are evident there on the early aerial photos. Uncertainty in “unmapped blind tidal chan-

nel” area is estimated as + 50%.

Differences between the three rivers in the distribution of channel types reflects the differences in landforms. The Skagit-Samish delta is dominated by estuarine channels, including abundant blind-tidal and distributary channels. This presumably reflects the divergent delta geometry, which creates a large amount of land in contact with saltwater.

The Snohomish River, by contrast, has a large area of freshwater distributary and blind channels. This presumably reflects the very low gradient of the subglacial-runoff-eroded

Snohomish River valley. In addition, because the entire valley is confined by valley walls, the absence of a divergent delta reduces the amount of estuarine channel relative to the Samish-Skagit delta. Finally, the lower Stillaguamish River, which flows in a relatively steep and confined valley, is dominated by estuarine channels, which make up a relatively small area.

p. 55

Table 7. Channel areas in ~1860 for the three study areas. Parenthetical values include channel area estimated as described in the text.

Zone Channel Type Skagit- Stillaguamish Snohomish Samish (ha) (ha) 2/ (ha) 1/

Estuarine Mainstem 6 0 0 Emergent Distributary 261 186 80 Distributary/Blind Tidal 129 0 3 Tributary 6 0 0 Connecting 212 16 0 Mapped Blind Tidal 99 31 14 Unmapped Blind Tidal 3/ (110 est.) (20 est.) (10 est.) Estuarine Mainstem 36 0 0 Scrub- Distributary 93 8 162 Shrub Distributary/Blind Tidal 24 0 0 Tributary 5 0 0 Mapped Blind Tidal 0 4 0 Unmapped Blind Tidal 3/ (90 est.) (20 est.) (40 est.) Tidal Mainstem 134 148 188 Freshwater Distributary 83 7 265 Floodplain Slough 0 0 43 Tributary 20 12 45 Distributary/Blind Tidal 6 2 0 Mapped Blind Tidal 0 0 20 Unmapped Blind Tidal 3/ (70 est.) (4 est.) (40 est.) Freshwater Mainstem 71 56 128 Distributary 71 0 0 Floodplain Slough 50 0 12 Tributary 54 0 3

TOTAL 1,630 510 1,050

1/ Areas estimated from non-polygon channels as described in text: EE-D=2 ha; EE- B/D=1; ES-B/D=1; ES-TRIB=2 ha; F-D=5 ha; F-M=12 ha; F-SL=1 ha; F-TRIB=18 ha; TF- B/D=3 ha; TF-D=2 ha; TF-TRIB=1 ha. 2/ Areas estimated from non-polygon channels as described in text: F-TRIB=3 ha; TF- TRIB=9 ha. 3/ “Unmapped blind tidal channels” estimated as explained in the text.

p. 56

16,000 A. SK-SA

14,000 Forest-Terrace Forest-Floodplain 12,000 Scrub-Shrub Emergent 10,000

8,000

6,000

4,000

2,000

0 4,000 B. ST 2,000

Land Area (hectares) 4000 C. SN

2000

NON-

TIDAL RIVERINE- WETLAND

ESTUARINE PALUSTRINE

Figure 16. “Historic” (~1860) area of wetlands, forested floodplain, and forested terrace in the (A) Skagit-Samish delta; (B) Stillaguamish estuary; (C) Snohomish River valley.

p. 57

A. SK-SA 800 Freshwater Tidal-Freshwater Estuarine Scrub-Shrub 600 Estuarine Emergent

400

200

200 B. ST

600 C. SN

400

Channel Area (hectares) 200

DIST TRIB MAIN BLIND SLOUGH

CONNECT BLIND/DIST

Figure 17. “Historic” (~1860) area of channels, within different zones defined by vegetation and hydrology, in the (A) Skagit-Samish delta; (B) Stillaguamish estuary; (C) Sno- homish River valley. p. 58

Habitat Change

It is beyond the scope of this report to detail the changes to habitat subsequent to the

“historic conditions” mapping. However, maps from subsequent years show the broad patterns and timing of changes to wetlands and channels.

Diking in the Skagit-Samish, and Stillaguamish river deltas occurred early; by ~1915, few estuarine wetlands remained (Figure 18). At the same time, nearly all of the freshwater wetlands present in ~1860 had been ditched and drained and were no longer shown on topographic maps. By the mid-20th century (~1945), a small amount of additional estuarine wetland was diked in the South Fork Skagit delta.

In the Snohomish River (Figure 19), diking and draining of estuarine and freshwater wetlands was as complete, but occurred somewhat later. By ~1900, significant portions of the two large freshwater marshes—Marshland and French Creek Marsh—remained, as did much of the Ebey-Island area riverine-tidal marsh. However, by ~1950, a dense network of ditches had replaced Marshland and the French Creek Marsh, and relatively small patches of estuarine wetlands remained.

p. 59

(Figures on following pages)

Figure 18. Skagit-Samish deltas and Stillaguamish River delta: (A) ~1915 (from USGS topographic maps Samish (1917) and Mt. Vernon (1911); (B) ~1945. From: USGS topographic maps Samish (1954), Mt. Vernon (1943), Stanwood (1943), Marysville (1941).

Figure 19. Snohomish River: (A) ~1900. North portion of map from USGS topographic

Snohomish (1895); south portion from Mt. Vernon (1911); (B) ~1950. North portion from USGS topographic Everett (1953); south portion from Marysville (1941).

p. 60

A. B.

Acknowledgments

This work was funded in part by a contract with the Skagit System Coop, LaConner, WA.

I thank Eric Beamer, Skagit System Coop, for initiating the project and providing input

throughout. The PRISM program (the Puget Sound Regional Synthesis Model) at the

University of Washington, and by a grant from the Bullitt Foundation provided additional

funding.

Amir Sheikh created digital layers in Arc/Info, with advice from Harvey Greenberg and assistance from Jeremy Bunn. The report benefited from review comments by Eric

Beamer, Andy Haas, David Montgomery, and Si Simenstad.

I thank Tim Abbe for the loan of his copy of the 1898 Army Corps map, “Index Map of

Skagit River, From its Mouth to the Town of Sedro, Washington.” I also thank the

Swinomish Tribal Planning Department, LaConner, WA, for kindly providing a digital

file of USC&GS map “La Conner Harbor T-2108,” 1892.

p. 63

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