Matanuska-Susitna Wetland Mapping

Cook Inlet Wetlands


DRAINAGEWAY  ECOSYSTEM Wetlands

A 2004 satellite photo showing a Relict Glacial Drainageway Ecosystem wetland (oorange tones) between Wasilla and Knk Arm.

Relict Glacial Drainageway wetlands are peatlands occupying relict, sometimes abandoned, drainageway features. These are linear features which drained once more extensive glaciers. Some may have formed along glacier margins. Some support modern streams but these streams are underfit. Many are now filled with peat. These peatlands are fens, with a stable high water table supported by ample groundwater throughflow that has had recent contact with mineral substrates.

A Relict Glacial Drainageway draining into Threemile Lake.


Table 1. Wetland Indicators in Drainageway Ecosystem map components throughout the Cook Inlet Lowlands.

Map Component

Peat Depth (cm)

Water Table (cm)

Redox features (cm) Saturation (cm) pH Specific Conductance µS/cm Plant Prevalence Index

DW1

6.5(3)
119.9 (3)
n/a

DW2

134(35)

8 (41)

144 (2) 2 (11) 5.9 (25) 126.4 (16) 1.55 (34)

DW3

111 (54) 22(51) 61 (6) 3 (16) 5.9 (24) 128 (18) 2.12 (49)

DW4

104(2) 23 (2)     4.5 (1)  

2.92 (2)

DW5

100(16) 33 (16) 59 (4) 0 (2) 5.3(4) 104 (2)

2.38 (15)

DW5A

62(32) 32 (29) 36 (7) 19 (6) 6.2(4) 164 (3)

2.58 (27)

Explanation:

All data from wetlands throughout the Cook Inlet Lowlands, not just from the Matanuska-Susitna Valley.

Numbers in paraentheses indicate number of samples.

Peat depth is a minimum, because some sites had thicker peat deposits than the length of the auger used (between 160 - 493 cm).

Water table depth is a one time measurement. At sites with seasonally variable water tables this measurement reflects both the conditions that year, and the time of year. If no water table was encountered, no value was recorded; use number of samples to aid interpretation.

Redox features with deep depths typically indicate deeper peat deposits, which mask redox indicators so the depth corresponds to the peat thickness.

pH and specific conductance measured in surface water or a shallow pit with a YSI 63 meter calibrated each sample.

Plant Prevalence Index calculated based on Alaska indicator status downloaded from the USDA PLANTS database, which may use different values than the 1988 list.


Table 2. Common soils and plant communities found in Drainageway Ecosystem wetlands.

Map Component

COMMON SOILS COMMON PLANT COMMUNITIES

DW2

STARICHKOF

DOROSHIN

Trichophorum caespitosum - Myrica gale

Carex aquatilis / Comarum palustre

Myrica gale - Carex livida

Myrica gale - Dasiphora floribunda

DW3

STARICHKOF

SALAMATOF

KILLEY

Myrica gale - Betula nana / Equisetum fluviatile

Myrica gale - Dasiphora floribunda

Myrica gale - Calamagrostis canadensis

Salix barclayi / Calamagrostis canadensis / Comarum palustre

DW4

STARICHKOF

KILLEY

Calamagrostis canadensis / Betula nana

Calamagrostis canadensis - Equisetum arvense

DW5

STARICHKOF

KILLEY

Salix barclayi / Calamagrostis canadensis - Equisetum arvense

Picea mariana / Ledum palustre ssp. decumbens

DW5A

STARICHKOF

KILLEY

Picea x lutzii / Salix barclayi / Equisetum arvense / Empetrum nigrum

Picea mariana / Equisetum sylvaticum - Ledum palustre ssp. decumbens


DRAINAGEWAY Ecosystem Wetland Map Components:

Map unit names are made of combinations of map components. A suffix 'c' idicates a created wetland, and a 'd' indicates a highly disturbed wetland.

DW1: Ponds in Drainageways.

DW2: Drainageways with water table near the surface most of the growing season. Often dominated by sedges, dwarf birch and/or sweetgale.

DW3: Drainageways often dominated by medium-height shrubs.

DW4: Drainageways dominated by Bluejoint reedgrass (Calamagrostis canadensis).

DW5: Draingeway margins dominated by thick Sphagnum moss, and often black spruce forests.

DW5A: Forested Drainageways.

Table 3.Summary of Matantuska-Susitna Valley and Cook Inlet Drainageway Map Unit occurrence (percentages of all wetlands).
Map Unit MatSu N Cook Inlet N Mat Su Hectares Cook Inlet Hectares Mat Su % Polygons Cook Inlet % Polygons MatSu % Area Cook Inlet % Area
DW1 5 9 2.7 19 1.43 0.04 0.01 0.01
DW12 2 17 28.1 209 0.11 0.07 0.07 0.11
DW12c 1 1 0.5 0.5 0.02 0.00 0.00 0.00
DW1-3 8 98 106 966 0.12 0.41 0.25 0.51
DW1-3d 1 1 2.0 2 0.02 0.00 0.00 0.00
DW1-4   8   243   0.03   0.13
DW1-5 1 10 1.3 88 0.02 0.04 0.00 0.05
DW1-5A   6   43   0.02   0.02
DW1c 3 3 2.6 2.6 0.05 0.01 0.01 0.00
DW2 39 117 225 735 0.59 0.49 0.53 0.39
DW21 12 63 65 826 0.18 0.26 0.15 0.44
DW23 27 162 129 1411 0.41 0.67 0.30 0.75
DW23d 2 2 3.5 3.5 0.03 0.01 0.01 0.00
DW24   7   42   0.03   0.02
DW2-4 1 17 0.6 102 0.02 0.07 0.00 0.06
DW25 2 12 7.2 115 0.03 0.05 0.02 0.06
DW2-5   12   97   0.05   0.05
DW25A 9 18 44 105 0.14 0.07 0.10 0.06
DW2-5A 3 26 13 271 0.05 0.11 0.03 0.14
DW2d 1 1 0.4 0.4 0.02 0.00 0.00 0.00
DW3 53 257 258 1485 0.8 1.07 0.60 0.79
DW31   3   6.7   0.01   0.00
DW32 19 171 153 1247 0.29 0.71 0.36 0.66
DW34   15   89   0.06   0.05
DW35 1 73 6 513 0.02 0.30 0.01 0.27
DW3-5   8   86   0.03   0.05
DW35A 28 190 132 1677 0.42 0.79 0.31 0.89
DW3-5A   36   401   0.15   0.21
DW3d 4 4 11.8 12 0.06 0.02 0.03 0.01
DW3T6   1   103   0.00   0.05
DW4 1 23 0.4 72 0.02 0.10 0.00 0.04
DW42   2   63   0.01   0.03
DW43   6   49   0.02   0.03
DW45   5   32   0.02   0.02
DW45A   10   74   0.04   0.04
DW4-5A   4   25   0.02   0.01
DW5 23 143 84 832 0.35 0.59 0.20 0.44
DW52   5   49   0.02   0.01
DW53 2 45 26 339 0.03 0.19 0.06 0.18
DW54   3   87   0.01   0.05
DW55A 9 97 57 711 0.14 0.40 0.13 0.38
DW5A 137 545 746 3453 2.06 2.27 1.75 1.84
DW5A2 6 26 99 327 0.09 0.11 0.23 0.17
DW5A3 52 186 332 1222 0.78 0.50 0.78 0.68
DW5A3d 1 1 2.0 2.0 0.02 0.00 0.00 0.00
DW5A4   2   2.6   0.01   0.00
DW5A5 2 68 12 857 0.03 0.28 0.03 0.46
DW5Ad 8 8 27 27 0.12 0.03 0.06 0.01
DWR 20 120 208 1268 0.30 0.50 0.49 0.68
DWRd 1 1 3.2 3.2 0.02 0.00 0.01 0.00

Do I Need a Permit?

Downloads:

Shapefile

1987 Delineation manual

2007 Regional AK Supplement

Methods, metadata

Maps and posters


Contact:
Mike Gracz
Kenai Watershed Forum 
PO Box 15301
Fritz Creek, AK  99603
13 January, 2010