Rocky Mountain Paddleboard - Union Reservoir
Lower Boulder Ditch near Rocky Mountain Paddleboard - Union Reservoir
About this river
Lower Boulder Ditch is a 21.3 mile canal near Rocky Mountain Paddleboard - Union Reservoir in Colorado. Streamflow is measured at the USGS gauge Boulder Creek at Mouth near Longmont, CO (site 06730500). The National Hydrography Dataset places it at stream order 6. Reach geometry comes from the USGS National Hydrography Dataset.
Typical flow by month
1927 to 2026
Lower Boulder Ditch typically runs highest in June, at a median 116 cfs, and lowest in August, at 5.7 cfs. The highest flow on record for any single day is 8,910 cfs, in 2013.
| Month | Typical (cfs) | Usual range (cfs) | Relative level |
|---|---|---|---|
| January | 52 | 35 to 66 | |
| February | 51 | 34 to 68 | |
| March | 48 | 26 to 76 | |
| April | 52 | 29 to 100 | |
| May | 102 | 21 to 222 | |
| June | 116 | 19 to 300 | |
| July | 9.7 | 4.2 to 27 | |
| August | 5.7 | 2.9 to 14 | |
| September | 7.2 | 3.0 to 22 | |
| October | 28 | 8.2 to 54 | |
| November | 46 | 21 to 70 | |
| December | 53 | 29 to 70 |
Typical is the median of each month’s daily median values, and the usual range runs from the median 25th to the median 75th percentile, across about 73 years of record. Statistics published by the US Geological Survey for Boulder Creek at Mouth near Longmont, CO (site 06730500). Conditions on any given day can fall well outside the usual range. Check the current reading before you go.
Embed this gauge on your site
Paste this snippet anywhere, an outfitter page, a club site, a trip report, to show Lower Boulder Ditch's live streamflow, water level and 7-day trend. It reads the USGS gauge directly, updates itself, and links back here.
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