There are several USGS gages on the Penobscot River.

• East Branch Penobscot (Grindstone)
• West Enfield
• Eddington
• Bangor

In addition, the National Weather Services’ Advanced Hydrological Prediction Services provides the following forecasts:

• East Branch Penobscot (Grindstone)
• West Enfield
• Eddington
• Bangor

Correlations

The USGS gauge at Eddington provides the best guidance for those paddling the stretch of the river between Old Town and Brewer, which has the most difficult rapids:

Less than 3 feet: Low water. Rapids may be scratchy, but are less likely to swamp open boats. Careful route finding may be necessary.

3 to 7 feet: Medium Water. Best flows for clean lines, but may be challenging for loaded boat. Canoes should be outfitted with flotation. Portaging may be appropriate, especially early season.

Greater than 7 feet: High water. Long swims possible.