The Influence of Hillside Springs on Subalpine Streamwater
Rocky Mountain Research Station
& Fraser Experimental Forest
crhoades@fs.fed.us
Chuck Rhoades, Natalie Quiet, Kathleen Dwire & Kendra Brewer
Springwater versus Streamwater
Plant Associations & Soil Conditions
Historic Context of Current Research
Treeline Zone
Species Name/ Occurrence Mean
(# springs)
Cover
Salix planifolia (3)
Caltha leptosepala (3)
Senecio triangularis (3)
Saxafraga odontoloma(3)
Moss spp. (3)
Subalpine Forest
Herb dominated
Senecio triangularis (12)
(3000 – 3375 m)
Senecio triangularis Saxifraga odontoloma (12)
Cardimine cordifolia Cardimine cordifolia (10)
Mitella petandra (11)
1 Carsey, K., G. Kittel, K. Decker, D.J. Cooper, and D.
Luzula parviflora (10)
Culver. 2003. Field Guide to the Wetland and Riparian
Carex aquatilis (7)
Plant Associations of Colorado. Colorado Natural
Moss spp. (12)
Heritage Program, Fort Collins, CO.
(3375 – 3500 m)
Willow shrubland
Salix planifolia
Caltha leptosepala
Fig. 7
CoverRange
(%)
(%)
47
18
21
20
70
21
20
14
10
3
16
73
10 – 100
5 – 40
5 – 45
5 – 25
35 – 90
5 – 90
5 – 65
1 – 65
1 – 25
1–5
5 – 85
5 – 100
Stream
Anions
1953 Photo
Fig. 4
7.5
Landscape Controls on
Spring Chemistry
Treeline Zone
Near Stream Channel
East Aspect Slopes
West Aspect Slopes
3,250 m
pH
200
400
800
ab
20
Springs
-
NH4
6.0
60
Conductivity
(μS / cm-1)
a
DON
50
Sodium
(μeq L-1)
40
ab
40
200
50
10
0
0
Fig. 10
Potassium
(μeq L-1)
Fig. 11
10
b
20
40
20
800
3200
3000
3400
3200
ANC
(μeq L-1)
80
3400
3000
3200
3000
0
ANC
(μeq / L)
300
a
Dissolved Organic N (μg/L)
ab
400
3,000 m
a
b
40
Sulfate
(μeq L-1)
8
Chloride
(μeq L-1)
20
6
60
40
4
40
20
200
20
2
20
0
0
0
3400
3000
3200
3000
3400
Elevation (m)
Elevation (m)
3200
3000
Elevation (m)
The ionic concentration of springwater increases with
decreasing elevation as does streamwater.
On the East aspect springs, the high variability of elements
released by mineral weathering may correspond to zones
of geologic faulting.
Fig. 12
Total N
Fig. 5
0
East
Treeline Near
West
Channel Slopes Slopes
0
60
East
Treeline Near
West
Channel Slopes Slopes
In general, the chemistry of springs emerging within the Treeline zone is distinct from
subalpine & Near Channel springs (Fig. 6). Concentrations of most dissolved ions are
significantly lower in the upper elevation springs.
*
5
p = 0.10
DON
40
NH4+
20
0
0
80
Historic Recommendations / Current Objectives
60
40
3200
Water
Temperature
1
2
J. Retzer. 1953. Characteristics of Springs in
Fool Creek. Rocky Mtn. For. & Range Expt. Sta.
High nitrate & low ammonium concentrations of Treeline springwater agrees with
greater nitrification & nitrate leaching measured in alpine soils at Fraser & elsewhere
(See Adjacent Poster). Similar Treeline & Near Channel springwater nitrate suggests
that groundwater flowpaths link these landscapes.
NO30
Old Growth
(n = 17)
*
Regenerating
Clear Cut (n = 15)
3
4
Flow Class
1
2
3
4
Flow Class
Decreasing Discharge
Springwater temperature increased as
discharge declined.
At low flow springs nitrate declined
dramatically & organic N increased
slightly.
Fig. 13
4
50 years after harvesting,
dissolved inorganic & organic N
concentrations are lower in
springs emerging within
recovering stands than in uncut
forest.
Spring water temperature is no
different between forest
conditions.
3
The similar ionic composition of East Slope & Near Channel springs combined with
greater density & higher discharge of East Slope springs (Fig. 3 & 11) suggests that
springs originating on this aspect may have a predominant influence on basin-scale
aqueous chemistry.
Nitrate - N
(μg L-1)
80
80
60
Flow Relations
10
100
100
Conductivity
(μS cm-1)
100
Harvest Effects
30
0
0
10
10
500
60
4
100
3400
b
DON
(μg L-1)
80
20
ab
30
100
Water Temperature
(oC)
2
0
a
Discharge
Relations
Springwater
6
400
400
b
300 600 900 1200 1500 1800 2100 2400
Streamwater
8
100
10
40
0
Tim e
Ammonium-N (μg/L)
a
200
Fig. 3
+
150
600
b
6.5
1054 2 ft / 321 3 m
Au g 9th - 13th 200 5
2
NO3
Treeline Zone
Near Stream Channel
East Aspect Slopes
West Aspect Slopes
200
Calcium
(μeq L-1)
600
1000
30
7.0
Upper Fool G auge
4
5
600
Elevation
Gradients
3400
a
40
0
9,800 ft
10
The average mid-day temperature of water emerging at springs was equal to the daily minimum
streamwater temperature at the upper Fool Creek gauge (Fig. 9).
0
Nitrate-N (μg/L)
20
10,600 ft
10,200 ft
To evaluate the [forest harvest] treatment program on
the occurrence and water yield of springs.”
Fig. 6
ab
11,000 ft
To collect water samples from the more vigorously
flowing springs for analysis of salts present.
15
Temperature (oC)
To relate the emergence of springs to geologic
structures or other features that may have influence
on their surface emergence.
0
9548 ft / 2910 m
Aug 9th - 13th 2005
6
Springwater nitrate was higher, but organic N did not differ from streams (Fig. 8).
μg N / L
To classify the water-yielding ability at the surface of
each spring …
11,400 ft
p = 0.17
20
Cations
-200
Low er Fool Gauge
Major Ion Concentration (μeq / L)
The organic horizon averages 20 cm deep and extends to > 60 cm in 20%
of sampled seeps (Fig. 4). Total soil depth (organic + mineral) to gravel or
bedrock averaged 40 cm and was >120 cm for several seeps.
In 1950 and 1953, several years prior to harvesting of the Fool Creek watershed, RMRS
soil scientist John Retzer surveyed and characterized wetland communities throughout
the basin. Retzer’s groundwork and preliminary recommendations have not been
revisited for a half-century.
“To locate and plot … all seeps and springs in the
watershed.
25
30
Historic Characterization of Fool Creek Springs
Retzer’
Retzer’s Objectives
30
8
Concentrations of dominant cationic & anionic constituents of springwater exceed Fool Creek
streamwater (Fig. 7).
2005 Photo
3,500 m
-400
Fig. 9 1
10
Springs
Stream
35
0
-600
Dense willow shrublands differentiate the seep communities found on
flatter topography and sparse forest canopy of the treeline zone from forbdominated herb strata of springs that emerge within closed-canopy
subalpine forest, often on steeper slopes.
Yellow flowered plant is Senecio triangularis
used by original researchers to spot the
wetland communities.
Na+ Mg2+ K+
ANC Ca2+
Springs
The floral communities surrounding the spring openings are typical of
central Rocky Mountain forested and riparian wetlands underlain by
Precambrian bedrock.
Fig. 2. View down slope across a Fool Creek seep.
Fig. 8
40
SO4-2
o
Wetland Plant
Association1
Water Temperature ( C)
Elevational Zone
Dissolved N (μg / L)
Overview
In high-elevation watersheds, more than 90% of snowmelt water passes
through near-surface flowpaths before entering the stream channel.
Groundwater discharges from isolated and clustered springs generating
ephemeral, intermittent and permanent flow in headwater stream channels.
At the Fraser Experimental Forest, 157 hillside springs are distributed
throughout the 290-hectare Fool Creek watershed. This preliminary report
describes results from synoptic sampling of 39 randomly selected springs in
alpine and subalpine portions of the catchment.
p = 0.09
Old Growth
(n = 17)
Regenerating
Clear Cut (n = 15)
Future
Directions
Identify seasonal patterns & linkages among springs and between springs & streamwater
Assess long-term effect of harvesting on edaphic, vegetation, snowpack & hydrochemical conditions of
spring network