Table 1.  Travel time of tracer between tracer-monitoring sites in Daisy Creek and the Stillwater River, Montana, August 24-25, 1999

         [Chloride concentrations are dissolved.  Abbreviations:  C50, concentration midway between the plateau and ambient concentrations; mg/L milligrams per liter]

 

Tracer-monitoring site (fig. 2)

Site number (fig. 2)

Chloride concentration (mg/L)

Arrival time (minutes)

Travel  time through subreach1 (minutes)

Average velocity within subreach1 (feet per second)

 

 

Pre-injection

Plateau

C50

 

 

 

T-1

104

0.45

118

59.2

7

7

0.25

T-2

1,340

.58

29.0

14.8

46

39

.53

T-3

9,925

.76

8.90

4.83

2577

2531

.27

T-4

12,410

.21

1.70

.96

3720

3143

.29

1Subreach is defined as the reach between the indicated site and the next upstream tracer-monitoring site or, for site T-1, the tracer-injection site.

2Arrival and travel times are approximate because samples were collected every 2 to 4 hours, which limited the temporal resolution.

3Arrival and travel times are estimated from data for departure of tracer because data for tracer arrival indicated that tracer arrived at site T-4 prior to tracer arrival at site T-3.