| Alder Brook | |
| Name Other: | Tributary to West Branch French Creek |
| Map Size: | 300 |
| Pushpin Map: | Pennsylvania#USA |
| Pushpin Map Size: | 300 |
| Pushpin Map Caption: | Location of Alder Brook mouth |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Pennsylvania |
| Subdivision Type3: | County |
| Subdivision Name3: | Erie |
| Subdivision Type4: | Township |
| Subdivision Name4: | Venango |
| Length: | 2.93miles[1] |
| Discharge1 Location: | West Branch French Creek |
| Discharge1 Avg: | 12.63cuft/s at mouth with West Branch French Creek[2] |
| Source1: | divide between Alder Brook and LeBeouf Creek |
| Source1 Location: | about 2 miles east of Bogus Corners, Pennsylvania |
| Source1 Coordinates: | 42.0661°N -79.8961°W[3] |
| Source1 Elevation: | 1335feet[4] |
| Mouth: | West Branch French Creek |
| Mouth Location: | about 3 miles NNW of Lowville, Pennsylvania |
| Mouth Coordinates: | 42.0575°N -79.8417°W |
| Mouth Elevation: | 1299feet |
| Progression: | West Branch French Creek → French Creek → Allegheny River → Ohio River → Mississippi River → Gulf of Mexico |
| River System: | Allegheny River |
| Tributaries Left: | unnamed tributaries |
| Tributaries Right: | unnamed tributaries |
| Bridges: | Wattsburg Road, Phillipsville Road |
Alder Brook is a 2.93miles long tributary to West Branch French Creek that is classed as a 1st order stream on the EPA waters geoviewer site.[1]
Alder Brook rises in Venango Township of eastern Erie County, Pennsylvania and then flows east to meet West Branch French Creek north of Lowville.
Alder Brook drains of Erie Drift Plain (glacial geology). The watershed receives an average of 46.2 in/year of precipitation and has a wetness index of 473.57.[5] The watershed is about 41% forested.[2]