Band 48, Heft 2 Boss-Verlag, Kleve Juni 1994
C O M P A R I S O N O F T H E W A T E R D R A I N A G E F R O M A N A C T I V E N E A R - S L O P E R O C K G L A C I E R A N D A G L A C I E R , S T . E L I A S M O U N T A I N S , Y U K O N T E R R I T O R Y
With 8 figures and 1 table
S T U A R T A . H A R R I S , W A Y N E K , B L U M S T E N G E L , D E N I S E C O O K , H . R O Y K R O U S E a n d G E R R Y W H I T L E Y
Zusammenfassung: Vergleich der Entwässerung eines aktiven Hangfuß-Blockgletschers und eines Gletschers, St. Elias Mountains, Yukon-Territorium
Ein Vergleich der Entwässerung des aktiven Block- gletschers östlich des Slims River mit dem glazialen Abfluß des Slims River läßt erhebliche Unterschiede erkennen.
Wassertemperaturen, p H , Abflußregime u n d Sediment- fracht zeigen markante tages- und jahreszeitliche Schwan- kungen gegenüber dem Abfluß des aktiven Blockgletschers.
Entsprechend den niedrigen Temperaturen des Ursprungs- gebietes zeigt der Gletscherabfluß negativere 81 80 - W e r t e . Die elektrische Leitfähigkeit des Wassers aus dem Block- gletscher ist etwa doppelt so hoch wie beim Gletscherabfluß.
Die Entwässerung des inaktiven Hilda-Blockgletschers (nach G A R D N E R u. B A J E W S K Y 1 9 8 7 ) gleicht mehr dem Gletscherabfluß als dem Abfluß des in dieser Studie unter- suchten aktiven Blockgletschers.
T h e data presented here for the rock glacier was col- lected during the 1985 field season and the Slims River data was obtained during the next four years.
This data allows valuable insights to be gained by comparing the general characteristics of these hydro- logical regimes on a diurnal and seasonal basis.
Specific parameters include water temperature, drainage, p H , salinity, 81 80 and sediment concen- tration.
If climatic warming occurs, these sources will tend to supply an increasing proportion of the water used by M a n in many alpine and arctic areas. This study will also establish whether the outflow from the front of a rock glacier can be used to establish whether it is active or inactive.
Introduction
The water held in solid form in glaciers and active rock glaciers represents a significant water resource
( B A R S C H 1978; C O R T E 1976) that affects the flow regimes and water quality of the streams emanating from their termini. Since the water is used by M a n downstream, it is desirable to know more about the modifications this water makes to the rivers into which it flows. This study compares the summer flow regimes and water quality of the contributions of two streams at Kluane, Yukon Territory, one coming from the front of an active rock glacier and the other largely supplied by glacial meltwater.
This will have a more immediate additional use in providing the criteria for distinguishing between active rock glaciers and inactive rock glaciers ( J O H N - SON 1987). G A R D N E R and B A J E W S K Y (1987) provided some data on the nature of the flow of streams from an inactive rock glacier in the Rocky Mountains of Alberta, and there is considerable, if scattered, literature on the variable water quality and discharge characteristics of glaciers (e. g. K J E L D S E N 1983, and the references contained therein for Norway). Unfor- tunately, data for proven active rock glaciers is lack- ing. It is impossible to find an active near-slope rock glacier adjacent to a glacier and with similar summer discharge, so differences in scale are inevitable.
Study Sites
T h e two catchments chosen were the springs at the front of the active rock glacier along the east side of the Slims River Valley (see B L U M S T E N G E L 1988; B L U M - S T E N G E L a. H A R R I S 1988) and the Slims River at the Slims River bridge on the Alaska Highway (Fig. 1). At least 80% of the "normal flow" of the Slims River is derived from discharge from the terminus of the Kaskawulsh Glacier, 22 km upstream from the bridge
( B R Y A N 1972, 1974). T h e glacier drains 2020 k m2, and probably accounts for a substantially larger pro- portion of the flow of the Slims River in summer due to the lower flow of the other tributaries, as indicated by extrapolation of asynchronous flow records (Glaciology Divison 1977).
T h e active lobate rock glacier on the east side of the Slims River is 1.7 km long and 0.6 km wide where it spreads out onto the valley floor ( B L U M S T E N G E L 1988;
B L U M S T E N G E L a. H A R R I S 1988). It is developed in a diamicton with greenstone clasts up to 20 cm long that originate at about 1230 m elevation below a cliff on the valley side. T h e valley was deglaciated about
12,500 ± 200 years B . P . (Y-1386, D E N T O N a. S T U I V E R
1966). T h e lower portion of the rock glacier is forested with a spruce-lichen woodland and has a thin loess cover over the rocks forming the rock glacier. This loess is added to by saline silt blown from the nearby
Fig. 1: Drainage of the Slims River valley above K l u a n e L a k e and location of the study sites. Site 1 is the Slims River Bridge and site 2 is at the toe of the East Slims rock glacier
Entwässerung im Slims River-Tal oberhalb des Kluane Lake u n d Lage der Untersuchungsstellen. Stelle 1 ist die Slims River-Brücke und Stelle 2 liegt am unteren Ende des East Slims-Blockgletschers
Slims River delta by northerly winds each winter.
T h e rock glacier has ploughed into alluvial silts of the Kaskawulsh flood-plain so that a silty push-lobe is present along the rock glacier front. From this front several streams emanate (Fig. 2).
T h e Kaskawulsh glacier is one of a n u m b e r of large outlet glaciers flowing northwards from the major icefields of the St. Elias range, and its meltwater feeds two rivers: the Kaskawulsh River flowing east to join the Alsek drainage, and the Slims River, which flows north into Kluane Lake.
T h e discharge of the Slims River is augmented by four major tributary streams: Vulcan Creek on the east side and Canada, Bullion and Sheep Creeks on the west, with a combined area of 436 k m2 (Fig. 1).
F A H N E S T O C K (1969) carried out a study of the flow regime of the Slims River, showing that its discharge
varied from 318 m3/sec (11 250 cfs) in late summer to 0.2 m3/sec (8 cfs) in winter. H e postulated that peak flows could reach 566 m3/sec (20 000 cfs). F A H N E - S T O C K also observed large variations in channel pat- terns and sediment transport, while the Glaciology Division (1977) emphasizes the evidence for periodic sudden outflows of water resulting from the release of water ponded in one of the 35 glacier-dammed lakes along the Kaskawulsh glacier.
Methods Used
All water temperatures were measured using a mercury in glass thermometer (to ± 0 . 5 ° C ) . In the case of the spring water below the rock glacier, the thermometer was placed in the centre of flow, not
Fig. 2: Location of the springs on the terminus of the rock glacier Lage der Quellaustritte am Fuß des Blockgletschers
more than 1 m from where the spring issued from the rock glacier front. T h e temperature data for the Slims River was obtained under the bridge at the Alaska Highway. A wooden platform located under the bridge allowed the water temperature to be measured 2 m from the bank of the river. Air temperature readings were provided by a Lambrecht recording hygrothermograph located at the snout of the rock glacier, and were checked by a YSI thermistor.
Precipitation was measured during the 1985 summer season at the rock glacier site using a Forester 8" rain gauge which was read to + 0.01" once each day, and totalled 127 m m for J u n e , J u l y and August.
Plywood (either 90° or 60°) V-notched weirs were installed on the springs at the front of the rock glacier, depending on the flow. A gauging staff was emplaced in each one for measuring stream stage. Discharge was then determined following the methods outlined in BS 3680 (1965) using the equations:
60° V-notch D = 2451.650 x H2-5
90° V-notch D = 4267.487 x H2 5
where D is discharge in litres/min"1; H is head of water (feet) flowing over the weir.
O n the Slims River, a gauging staff was fixed to the bridge pier at the Alaska Highway. No discharge estimates were made using the stage data for the Slims River due to inadequate knowledge of channel geom- etry.
At both sites, visual readings of stage were made once or twice a day, from M a y to August 1984 and 1987, to determine the general pattern of variation during the summer. Diurnal variations were studied at both sites by carrying out visual readings of stage at 1/2 hour (Slims River site) and 1 hour (rock glacier site) intervals over a continuous 30-hour period in mid-summer.
At the same time, water samples were collected in clean 30 ml plastic Nalgene bottles that were dipped in the water and rinsed several times before the actual sample was collected. Spring water from the rock glacier was collected from the centre of stream flow, less than 1 m from where the spring emanated from the front of the rock glacier. T h e Slims River water samples were collected beneath the bridge at the Alaska Highway. Samples for stable isotope analysis were stored frozen, whereas those for p H and conduc-
tivity were taken to the Kluane Lake Research Station (AINA) and analyzed immediately. It has been postulated that the water coming from rock glaciers has a higher conductivity and mineral content (see
C O R T E 1 9 7 8 ) .
T h e 8l aO ratio was determined in the Mass Spectrometry Laboratory, Department of Physics, University of Calgary. 10 ml of water was pipetted into standard glass bottles with 24 bottles being screw- ed onto a manifold with a vacuum-tight fitting. Each run consisted of 20 samples and four standards. Air and other dissolved gases were pumped from the water through capillaries ( R O E T H E R 1 9 7 0 ) . Then C 02 was introduced and allowed to equilibrate with the sample overnight. The analysis was run using a 90° Neir-type mass spectrometer built around Micro- mass 903 components. 8l sO is expressed as per mil (%o) deviations from Standard M e a n Ocean Water based on the standard samples. T h e conductivity was measured using a H A C H portable conductivity meter with automatic temperature compensation. p H was determined using a Fisher Accumet p H meter, calibrated against 4.0, 7.0 and 10.0 p H standard solu- tions.
Water samples for analysis of sediment concentra- tion were collected twice a day from the Slims River.
Analyses were performed by the Field Laboratory of the Department of Indian Affairs and Northern Development in Whitehorse. Turbidity was measur- ed by attenuation of a light beam passing through the sample using a Hellige turbidity meter. Suspended solids (including settleable solids) were measured gravimetrically by filtering a well-mixed sample through a weighed standard glass-fibre filter and dry- ing in an oven to constant weight at 1 0 3 - 1 0 5 ° C (see method 2 0 9 C , G R E E N B E R G et al. 1 9 8 5 , pp. 9 6 - 9 7 ) .
Results
For convenience, these will be divided into specific parameters:
1. Temperature
Water temperature of the spring water from the rock glacier showed negligible diurnal variations, and maintained temperatures between 1 °C and 2 °C for two entire summer seasons ( 1 9 8 4 and 1 9 8 5 ) . This was in marked contrast to the water temperature in the Slims River which showed substantial variations both diurnally (Fig. 3) and seasonally (Fig. 4). T h e varia- tions in the water temperature in the river closely
followed those of the air temperature for most of the summer, which is to be expected along a shallow braided river.
2. Diurnal Flow Regimes
The flow regime of the rock glacier springs (Fig. 5) was essentially constant when measured at 1 hour
TEMPERATURE
Mean=204.5 ^Scrrr1
I I I i
-25-
-26 1 1 1 1 1 1 1 1
9 12 15 18 21 24 3 6 S 12 15
27th June, 1989 | 28t h June, 1989 Fig. 3: Diurnal variations in the properties of the Slims
River water based on sampling at 30 minute intervals on J u n e 27-28, 1989
Tagesschwankungen der Wassereigenschaften des Slims River, gestützt auf halbstündliche Messungen am 27.-28. J u n i 1989
Mean-24.931%o
20 - G
o
% s
•83 10-
«j 8.
S g a 0.
50- I 40-
£ 30-
<L>
S 20-
4-
2 -
<Yit
MEAN DAILY TEMPERATURE
/ Y Ç N V
A
1 0 0 1
SUSPENDED SOLIDS
May June July August
1987
c E - CO <D
5 0 - a) CD ra ..c 0 u>
a 0 •
21
Fig. 4: Seasonal variations in the properties of the Slims River water during the summer of 1987
Saisonale Schwankungen der Wassereigenschaften des Slims River im Sommer 1987
intervals for 29 hours in 1985, and this was found to be typical of all these streams. Measurements taken in 1984 using a Leupold and Steven's Type Chart Recorder over several 3-day periods during the sum- mer also showed no diurnal variations ( B L U M S T E N G E L
1988). However, in the Slims River (Fig. 3), the flow
5 10 15 2 0 11 6 11 16 J u l y 15 ' J u l y 16
Fig. 5: Diurnal flow regime of spring no. 3, measured once every h o u r on J u l y 15-16, 1985
Tageszeitliches Abflußregime der Quelle N r . 3; stünd- liche Messungen am 15. u n d 16. J u l i 1985
regime showed a marked diurnal variation which was offset from the peaks of air temperature by approx- imately 9-10 hours due to the distance from the snout of the glacier.
3. Seasonal Flow Regimes
T h e seasonal flow regime of the rock glacier springs (Fig. 6) showed a recession in the spring (2201itres/min or .0037 m3/sec) at Spring 2 at the time of the snow-melt, followed by a fairly flat base flow.
Very heavy or prolonged rains caused a peak with a delay time of 10-14 days, suggesting that the precipi- tation entered the active layer and flowed laterally down slope above the thawing front to feed the stream at the front of the rock glacier. T h e base flow was slightly higher in late July and early August when the air temperatures were at a m a x i m u m , and the discharge peaks were higher for a given rainfall event when the air temperatures at the time of the precipita- tion were over 15 ° C , indicating more heat input into the upper layer of permafrost, resulting in greater melting of ground ice.
T h e stage of the Slims River is low until the spring thaw, when there is a rapid increase due to melting of the snow pack. This is followed by a slow rise through to mid-August (Fig. 4). Although no data were col- lected after the middle of August, a visual assessment of flow was made early in September, indicating a substantial decrease in flow. This correlates with lower maximum and minimum daily air tempera- tures and far shorter daylight hours.
4. Sediment Load
There were no visible sediments in any of the spring waters from the active rock glacier, even at the
200
~ 150
<u 100- Ol
50-
June July August
E E 2 0 -
r 10- Q.
June
1
July
1
August1200-,
1 1 0 0 -
'E 1 0 0 0 -
o oo ^
"7 9 0 0 -
•O C O O
8 0 0 -
7 0 0 -
600
June 1 July 1 August
Fig. 6: Seasonal discharge of springs no. 1 and no. 2 with air temperature and precipitation for 1 9 8 4 (from B L U M - S T E N G E L a . H A R R I S , 1 9 8 8 , F i g . , 7, p . 6 9 2 )
Saisonale Entwässerung der Quellen Nr. 1 und 2 mit Lufttemperaturen und Niederschlag für 1984
time of snow melt. However, the turbidity of the Slims River water (Fig. 4) increases during the summer until peak flow is achieved in early August. T h e sedi- ment load of the Slims River has been shown to be derived primarily from ablation of the Kaskawulsh glacier and the release of its sediment load ( J O H N S O N ,
personal communication, 1989). Settleable and sus- pended solids are low until the end of J u n e when there is a large increase in ablation from the Kaskawulsh glacier. At that time, there was a change in the weather from predominantly cloudy days to clear,
O O 0) nj 0) a E
<D I -
E E c O 2 a O
£
2 0 -
1 0 -
8.4-1 8 . 2 - X 8 . 0 -
Q.
7 . 8 - 7 . 6 -
rJ~i 1 1 1 1 r 1 1 1- 20—1
1 0 -
i J \ P • r' - i l l
I I 10 20
June
- 1 1—
10 20 July 1 9 8 5
10 20 August
Fig. 7: Seasonal variations in conductivity of the springs in front of the rock glacier in 1985
Saisonale Schwankungen der Leitfähigkeit der Quellen am F u ß des Blockgletschers 1985
31 80>mean = -22.94 %o
Conductivity>mean = 933 (iS cm"1 Air Temperature > mean = 12.25 °C
Fig. 8: Diurnal variations in water chemistry for spring no. 1 based on one h o u r samples on J u l y 15-16, 1985
Tagesschwankungen wasserchemischer Kennwerte für Quelle Nr. 1 nach stündlichen P r o b e n a h m e n am 15. u n d 16. J u l i 1985
-Z/.U -¿J.U I I I I I 990 960 930 900 870
i i i i i 18 14 10 6
I I I L_
2 i
hotter weather. Suspended solids decrease with decreasing flow in mid-August. Apparently there is more limited erosion in the area during the snow-melt in the spring and the bulk of the sediment comes from the glacier.
There are minor peaks of low and high settleable and suspended solids that are not correlated with weather. These peaks may reflect debris flow occur- rences within the basin ( G U S T A F S O N 1 9 8 6 ; H A R R I S a.
G U S T A F S O N 1 9 8 8 ) or may be related to variable
discharge from the glacier itself ( F A H N E S T O C K 1 9 6 9 ) .
T h e variability in sediment yield and flow of the Slims River seen early in the season, which is not directly related to new precipitation, may be due to runoff connected with melting of the snow pack.
5. p H
T h e p H of the springs in front of the rock glacier showed fairly constant p H values (Fig. 7). Individual
Table 1: Comparison of the hydrology of streams below the Kaskawulsh Glacier, the aetive East Slims River Rock Glacier, and the inactive Hilda Creek Rock Glacier (from GARDNER a. BAJEWSKY 1987)
Vergleich der Abflüsse des Kaskawulsh Gletschers, des aktiven East Slims River Blockgletschers und des inaktiven Hilda Creek Blockgletschers
Property Glacier
Rock Active
Glacier
Predominantly inactive
( G A R D N E R a . B A J E W S K Y 1 9 8 7 )
(1) Water temperature
a. Diurnal Substantial fluctuations c. 7 ° C Substantial variation
Virtually constant
Between 1-2 °C Not studied
(2) Flow Regime a. Diurnal
b. Seasonal
Substantial range offset from air temperature.
Rises during s u m m e r as tem- perature rises. Heavy rains cause minor peaks with mini- mal delay. U p to 3.331/sec/km2
Virtually constant
Peak at snowmelt and then flat base flow punctuated by peak flows 10-14 days after heavy rains. U p to 0.0286 1/sec/km2
Substantial range directly proportional to air tempera- ture. Negligible offset.
U p to 0.349 1/sec/km2
(3) Sediment Load a. Turbidity b. Settleable &
suspended solids
Shows diurnal fluctuations with flow regime
Rises during s u m m e r . Low to high correlated with higher temperatures in mid J u n e . Rise until mid August.
Virtually constant but very low.
Direct relationship to flow and air temperature with substantial diurnal variability.
Increases after rains.
(4) Conductivity Decreases during summer. Approximately 2 times that below nearby glaciers.
Decreases during summer.
(5) p H a. Diurnal b. Seasonal
Over 1.0 p H unit variation.
0.7 p H unit, being more alka- line in August.
U n d e r 0.4 p H units range of variation.
(6) 81 80
Diurnal Related to air temperature.
M e a n -24.93%o ~ -2%o lower than mean local precipitation.
Related to air tempera- ture. M e a n -22.94%o = local precipitation.
s p r i n g s s h o w e d slightly different p a t t e r n s , a n d t h e m a x i m u m r a n g e r e c o r d e d in a s p r i n g d u r i n g t h e s u m - m e r w a s 0 . 4 p H u n i t s . T h e m e a n v a r i e d b e t w e e n 7.9 a n d 8 . 1 for t h e four s t r e a m s .
T h e r i v e r w a t e r s h o w e d m u c h g r e a t e r v a r i a b i l i t y in p H t h a n t h e s p r i n g s in front of t h e rock g l a c i e r . T h e p H of t h e S l i m s R i v e r w a t e r ( F i g . 4) slowly r o s e from a r o u n d 8 . 0 in M a y to a b o u t 8 . 7 in e a r l y A u g u s t a n d
t h e n d e c l i n e d . T h e r e w a s a l s o a d i u r n a l f l u c t u a t i o n of o v e r 1 p H u n i t ( F i g . 3).
6. C o n d u c t i v i t y
B o t h t h e w a t e r in t h e s p r i n g s e m a n a t i n g f r o m t h e r o c k g l a c i e r ( F i g . 7) a n d t h e c o n d u c t i v i t y of t h e S l i m s R i v e r w a t e r ( F i g . 4) d e c r e a s e d d u r i n g t h e s u m m e r .
This is probably due to leaching of salts during snowmelt from the saline, windblown silts that tend to be blown up-valley from the delta during winter onto the rock glacier and the lower salt content of the meltwater derived from both glacier ice and ground ice.
There was a noticeable inverse relationship be- tween air temperature and conductivity in the Slims River (Fig. 4), but a direct relationship between these variables in the case of the rock glacier (Fig. 7). T h e latter results are not due to using the temperature compensation, since the measurements were made under constant temperature conditions ( G U R N E L L a.
C L A R K E 1 9 8 7 ) .
7. 81 80
This was measured in the samples collected at regular intervals (30 or 60 minutes) during 30-hour studies at both locations (Figs. 3 a. 8); variations in the S1 80 of the water were quite small. In the case of the water from the rock glacier, the 81 80 was closely related to air temperature, but the mean values were 2%o more negative for the river water, reflecting the colder environment on the icefields where the ice was formed (see M A C P H E R S O N a. K R O U S E 1967; W E S T a.
K R O U S E 1972). However, this is a trend observed over a short period and the overall cycle of 8l sO values has not been determined.
Discussion and Conclusions
Only limited studies have been carried out on the hydrology of the streams below rock glaciers. Most of these were cases where the rock glacier was probably inactive, and this would appear to be true for the study of the Hilda rock glacier (see L U C K M A N a. C R O C K E T T 1 9 7 8 ) by G A R D N E R a. B A J E W S K Y ( 1 9 8 7 ) , which rep- resents the most thorough study reported in the literature. Thus we can summarize and compare their results with those reported above in Table 1.
Table 1 indicates that there are important dif- ferences between the outflows of active rock glaciers and glaciers. T h e springs in front of a rock glacier exhibit a steady flow with clear water, whereas the diurnal flow of glacial meltwater varies considerably and is turbid. T h e water from the rock glacier has about twice the electrical conductivity of the glacial meltwater, showing the effect of the longer residence time. In addition, when the runoff is calculated for the two catchments (discharge/area), the average sum-
mer runoff for the glacier using the measurements of
F A H N E S T O C K (1969) is three orders of magnitude greater than the runoff calculated from the springs in front of the rock glacier (0.0286 litre/sec/km2).
T h e present results confirm and amplify those of most other authors, e. g. runoff and greater overall variability ( C O R T E 1978; J A C K S O N a. M A C D O N A L D
1980; J O H N S O N 1981; E V I N a. A S S I E R 1983 a, 1983b, 1984; H A E B E R L I 1985). T h e substantial difference in scale between the two catchments used in the present study does not appear to affect the results.
When the results noted by G A R D N E R a. B A J E W S K Y ( 1 9 8 7 ) are compared with the data presented in this study, it becomes apparent that their data are very dif- ferent from that for the active rock glacier along the east side of the Slims River. Instead, the stream below the Hilda rock glacier showed a variation more like meltwater below a glacier or a spring below a talus slope. Its runoff is also much higher. An anonymous reviewer commented that "their rock glacier overlies the Stephen-Eldon contact which is a major spring line in this part of the Rockies. In other words, their 'rock glacier' spring is actually a groundwater spring mantled by the rock glacier". T h u s , more work will be needed to establish what are the characteristics of in- active rock glaciers so as to complete this examination of the prediction by J O H N S O N ( 1 9 8 1 ) .
Both glaciers and rock glaciers represent an impor- tant storehouse of water in the form of ice in the mountains. Glaciers consist of about 97-99% pure ice, but in rock glaciers, ice makes u p only 4 0 - 6 0 % of the landform (e. g. B A R S C H 1978). Meltwater from these landforms modifies the flow regimes of the streams down-valley.
If climatic warming occurs, the active rock glaciers are likely to increase their output of melted ice. T h e discharge will probably remain relatively small and consistent in volume. Dissolved salts will be relatively high but the outflow will carry little suspended sedi- ment from the landform. Complete melting will take a long time. Glacial discharge will undoubtedly in- crease in volume and variability, with higher diurnal and seasonal peak flows ranging down to the usual minuscule flows in winter. In this case, the water will carry large quantities of sediment but comparatively low amounts of dissolved solids. T h e rate of response to the warming will also tend to be more rapid in the case of glaciers than in rock glaciers.
Climatic change involving a reduction of precipita- tion but without a change in temperature would result in retreat of the glaciers, but increased moisture storage in rock glaciers due to the decreased winter snow cover. However, if the mean annual precipita-
t i o n is less t h a n a b o u t 3 5 0 m m , t h e r e is t o o little m o i s t u r e s t o r e d i n t h e p e r m a f r o s t t o a l l o w for r o c k g l a c i e r m o v e m e n t , w h e r e a s glaciers m a y still o c c u r in p l a c e s w h e r e sufficient s n o w a c c u m u l a t e s e a c h y e a r . F o r e x a m p l e , t h e K a r a k o r u m R a n g e a n d in T i b e t
( H A R R I S , in p r e s s ) .
C o n v e r s e l y , a n i n c r e a s e in p r e c i p i t a t i o n w i t h o u t w a r m i n g w o u l d r e s u l t in i n c r e a s e d m o i s t u r e s t o r a g e in glaciers a n d m o r e m e l t i n g of t h e i n t e r s t i t i a l ice in r o c k glaciers. T h e c h a r a c t e r i s t i c s of t h e run-off from e a c h s o u r c e w o u l d n o t c h a n g e as l o n g as t h e r o c k glacier c o n t a i n s ice. H A E B E R L I ( 1 9 7 8 , F i g . 2) h a s p r e d i c t e d t h a t t h e r e will b e a v a l u e of p r e c i p i t a t i o n at w h i c h t h e e q u i l i b r i u m line o n glaciers d e s c e n d s b e l o w t h e l o w e r l i m i t of r o c k glaciers. W h e r e h i g h e r p r e c i p i t a t i o n o c c u r s , active r o c k glaciers c o u l d n o t form n o r p e r s i s t . H e l a t e r s u g g e s t e d t h a t t h i s critical a m o u n t of a n n u a l p r e c i p i t a t i o n is slightly g r e a t e r t h a n 2 5 0 0 m m i n t h e A l p s ( H A E B E R L I 1983).
F i n a l l y , if t h e r e w e r e a r e d u c t i o n in m e a n a n n u a l t e m p e r a t u r e w i t h o u t a c h a n g e in p r e c i p i t a t i o n r e g i m e , b o t h r o c k glaciers a n d glaciers w o u l d e n l a r g e a n d s t o r e m o r e m o i s t u r e . T h u s it is e s s e n t i a l to k n o w t h e n a t u r e of a n y c l i m a t i c c h a n g e before t h e r e s p o n s e of t h e t w o k i n d s of l a n d f o r m s c a n b e p r e d i c t e d . C o n - v e r s e l y , if t h e r e s p o n s e of b o t h rock g l a c i e r s a n d glaciers is k n o w n , t h e n a t u r e of t h e c l i m a t i c c h a n g e c a n b e inferred.
Acknowledgements
G r a t e f u l t h a n k s a r e d u e to P a r k s C a n a d a a n d t h e W a r d e n s of K l u a n e N a t i o n a l P a r k for t h e i r p e r m i s - sion to c a r r y o u t t h e s t u d y a n d for logistical h e l p in t h e field. T h a n k s a r e also g i v e n to D r . P E T E R G . J O H N S O N
for his c o m m e n t s o n t h e m a n u s c r i p t . T h e field w o r k w a s c a r r i e d o u t u s i n g f u n d s from N S E R C O p e r a t i n g G r a n t A 7 4 8 3 a n d N o r t h e r n T r a i n i n g G r a n t s to C O O K a n d B L U M S T E N G E L .
References
B A R S C H , D . : Active rock glaciers as indicators for discon- tinuous alpine permafrost: An example from the Swiss Alps. In: Proc., 3rd Int. Conference on Permafrost 1, 1978, 349-353.
B L U M S T E N G E L , W. K.: Studies of an active rock glacier, east side, Slims River Valley, Yukon Territory, C a n a d a .
Unpublished M . Sc. thesis, Department of Geography, University of Calgary, 1988.
B L U M S T E N G E L , W. K. a. H A R R I S , S . A . : Observations on an active lobate rock glacier, Slims River Valley, St. Elias R a n g e , C a n a d a . In: Permafrost: 5th Int. Conference Proc., Tapir Publishers, Trondheim, Norway, 1988, 689-694.
B O S T O C K , H . S.: Kluane Lake, Yukon Territory: Its
drainage and allied problems. Geological Survey of C a n a d a Paper, 1969, 69-28.
B R Y A N , M . L.: Variations in quality and quantity of Slims River water, Yukon Territory. In: C a n . J . Earth Sei. 9, 1972, 1469-1478.
- : Water masses in Southern Kluane Lake. - Icefield Ranges Research Project, Scientific Results 4, Amer.
Geog. Soc. a. Arctic Inst, of N. America, 1976, 163-169.
BS 3680: Methods of measurement of liquid flow in open channels, part 4A, Weirs and Flumes - thin plate weirs and ventin flumes. London: British Standards Institu- tion, 1965.
C O R T E , A. E.: T h e hydrological significance of rock gla- ciers. In: J . Glaciol. 17, 1976, 157-158.
- : Rock glaciers as permafrost bodies with debris cover as an active layer: A hydrological approach, Andes of M e n - doza, Argentina. In: Proc., 3rd Int. Conference on Per- mafrost, Edmonton, Alberta. National Research C o u n - cil, C a n a d a 1, 1978, 262-269.
D E N T O N , G. H . a. S T U I V E R , M . : Late Pleistocene strati- graphy and chronology, northeastern St. Elias M o u n - tains. In: Geol. Soc. Amer. Bull. 78, 1966, 485-510.
E V I N , M . : Caractéristiques physico-chimiques des eaux issues des glaciers rocheux des Alpes du Sud (France) . I n : Zeitschrift für Gletscherkunde u n d Glazialgeologie 20, 1984, 27-40.
E V I N , M . a. A S S I E R , A.: Glacier et glacier rocheux dans le Haut-Vallon du Loup, Alpes du Sud, France. In: Zeit- schrift für Gletscherkunde und Glazialgeologie 19, 1983a, 27-41.
- : Relations hydrologiques entre glacier et glacier rocheux: l'exemple de cirque de Marinet ( H a u t e - U b a y e , Alpes du Sud). In: J o u r n é e s de la Société Hydrotechni- que de France. Section de glaciologie. 21 and 22 M a r c h , 1983, Grenoble 1983b, 1-5.
F A H N E S T O C K , R . K . : Morphology of the Slims River. - Ice- field Ranges Research Project Scientific Results 1, 1969, 161-172.
G A R D N E R , J . S. a. B A J E W S K Y , I.: Hilda Rock Glacier stream discharge and sediment characteristics, Sunwapta Pass area, C a n a d i a n Rocky Mountains. In: G I A R D I N O , J . R . ,
S C H R O D E R , J . R . a. V I T E K , J . D. (Eds.): Rock Glaciers.
London 1987, 161-174.
G R E E N B E R G , A . E . , T R U S S E L L , R . R . a . C L E S C E R I , L . S . :
Standard Methods for the Examination of Water and Waste Water. American Public Health Association, Washington, D . C . , 16. Edition, 1965.
G U R N E L L , A. M . a. C L A R K E , M . J . (Eds.): Glacio-fluvial Sediment Transfer: An Alpine Perspective. Wiley and Sons, Chichester, England, 1987.
G U S T A F S O N , C . A.: Debris flows along the Slims River Valley, Kluane National Park, Yukon Territory. U n - published M . Sc. thesis, Department of Geography, University of Calgary, 1986.
H A E B E R L I , W.: Special aspects of high mountain permafrost methodology and zonation in the Alps. In: Proceedings, 3rd International Conference on Permafrost, vol. 1. Na- tional Research Council, O t t a w a 1978, 379-384.
- : Permafrost-glacier relationships in the Swiss Alps - to- day and in the past. In: Proceedings, 4th International Conference on Permafrost, vol. 1. National Academy Press, Washington, D. C. 1983, 415-420.
- : Creep of mountain permafrost: Internal structure and flow of alpine rock glaciers. Mitteilungen der Ver- suchsanstalt für Wasserbau, Hydrologie und Glaziologie 77, 1985, Zürich.
H A R R I S , S . A . : Climatic zonality of periglacial landforms in mountain areas. In: Arctic (in press).
H A R R I S , S . A . a. G U S T A F S O N , C . A.: Retrogressive slumps, debris flows and river valley development in icy, uncon- solidated sediments on hills and mountains. In: Geo- morph. 32, 1988, 441-455.
J A C K S O N , L . E . a. M A C D O N A L D , G . M . : M o v e m e n t of an ice-cored rock glacier, Tungsten, N. W. T., C a n a d a , 1963-1980. In: Arctic 33, 1980, 822-847.
J O H N S O N , P. G . : T h e structure of a talus derived rock glacier as deduced from its hydrology. In: Earth Sci. 18, 1981, 1422-1430.
K J E L D S E N , O . : Material Transportundersokelser i Norske Breelver. 1981. In: Norges Vassdrags-og Elektrisitets- vesen, R a p p o r t 1-83, Oslo 1983.
L E O P O L D , L . B . , W O L M A N , M . G . a. M I L L E R , J . P.: Fluvial Processes in Geomorphology. San Francisco 1964.
L U C K M A N , B . J . a. C R O C K E T T , K . J . : Distribution and characteristics of rock glaciers in the southern part of J a s p e r National Park, Alberta. In: C a n . J . Earth Sci. 15,
1978, 540-550.
M A C P H E R S O N , D. S . a. K R O U S E , H . R . : 1 80 /1 60 ratios in snow and ice of the H u b b a r d and Kaskawulsh Glaciers.
In: S T O U T , G. E. (Ed.): Isotope Techniques in the
Hydrological Cycle. Geophysical M o n o g r a p h 1, 1967, 180-194.
R O E T H E R , W.: W a t e r / C 02 exchange set-up for the routine
l sO assay of natural waters. In: Int. J . of Applied Radia- tion and Isotopes 21, 1970, 379-387.
W E S T , K . E. a. K R O U S E , H . R . : Abundances of isotope species in water in the St. Elias Mountains. In: Icefields Ranges Research Project Scientific Results 3, 1972, 117-130.
