## Facts

- Snow (plaintiff) owned and operated a downstream mill that relied on the flow of a stream for water power.
- Parsons (defendants) owned and operated a tannery upstream on the same stream.
- In running the tannery, defendants discharged waste or “spent” tan-bark into the stream above Snow’s mill.
- The bark floated downstream and accumulated in Snow’s millpond and at times entered the flume, causing occasional interference with Snow’s waterwheel and the flow of water to the mill.
- Snow’s mill was erected before defendants began using the stream in connection with the tannery, but not long enough beforehand to give Snow a prescriptive right to an unpolluted or unobstructed flow as against later riparian uses.
- The interference described in the findings was intermittent and, at least at times, could be removed without great difficulty.
- Evidence indicated Snow could have used a different type of wheel that would have been less affected by bark in the water.
- Snow brought an action on the case, alleging obstruction and interference with his use of water power.
- The matter was referred to a referee for factual findings; based on those findings, the county court entered judgment for Snow and awarded damages.
- Defendants appealed to the Vermont Supreme Court, disputing the legal standard governing competing riparian uses and challenging the treatment of evidence bearing on “reasonableness,” including proof of local custom.

## Issues

1. Whether an upstream riparian proprietor’s discharge of spent tan-bark into a stream, which sometimes obstructs a downstream proprietor’s mill operations, is actionable when the discharge may be part of ordinary industrial use of the watercourse.
2. Whether the “reasonableness” of a particular use of a stream—and the extent to which a downstream proprietor must submit to resulting inconvenience when the line is doubtful—is a question of fact for the trier of fact.
3. Whether evidence of the uniform local custom regarding such uses of streams (e.g., customary tannery practices) is admissible in deciding reasonableness.

## Decision

- The court affirmed the judgment for Snow.
- The court held that when the reasonableness of a particular use of a stream and the degree of downstream tolerance are doubtful, the matter is for the trier of fact (here, the referee/county court), not a pure question of law to be re-decided on appeal.
- The court held that evidence of the uniform custom of the country relating to the challenged use is admissible for the factfinder in determining whether the use is reasonable.
- Applying these points, the court declined to disturb the factfinder’s resolution and left the damages award in place.

## Legal Principles

- Riparian rights are correlative: each riparian owner may make beneficial use of the stream, but not in a manner that unreasonably interferes with other riparian owners’ lawful use.
- When the boundary between reasonable and unreasonable riparian use is uncertain, “reasonableness” is treated as a factual question for the jury or other factfinder.
- In deciding reasonableness, the factfinder may consider evidence of a uniform local custom concerning the kind of stream use at issue.
- A downstream proprietor may be required to tolerate some inconvenience from upstream uses that are found reasonable under all the circumstances, but unreasonable interference with the downstream owner’s use may support liability and damages.

## Conclusion

Snow v. Parsons holds that competing industrial uses of a stream are governed by a reasonableness standard: an upstream tannery’s discharge that interferes with a downstream mill may be actionable if found unreasonable, and when the line is doubtful the determination belongs to the factfinder, who may consider proof of uniform local custom; on that basis, the Vermont Supreme Court affirmed a county-court judgment awarding Snow damages for interference caused by spent tan-bark from the Parsons tannery.


Snow v. Parsons, 28 Vt. 459 (1856)