## Facts

- Lake Koshkonong is a shallow lake formed by a widening of the Rock River; small water-level changes significantly affect navigation.
- A 1917 dam raised water levels; after repairs completed in 2002, lake levels returned to DNR-approved targets, restricting boating and requiring longer piers for access to navigable water.
- The Rock-Koshkonong Lake District and related associations petitioned the Wisconsin Department of Natural Resources (DNR) under Wis. Stat. § 31.02(1) to raise the lake’s water levels above an earlier order.
- The DNR denied the petition, finding higher levels would harm adjacent wetlands through increased inundation and related ecological effects; many affected wetlands were privately owned and non-navigable.
- After a contested case hearing, an administrative law judge affirmed the DNR’s decision; the circuit court and court of appeals affirmed.
- In the administrative proceeding, the DNR gave substantial weight to wetland and habitat protection and largely excluded or discounted evidence of economic impacts from lower water levels on owners, businesses, recreation, and local tax revenue.

## Issues

1. What level of judicial deference, if any, applies to the DNR’s legal conclusions about its authority under Wis. Stat. § 31.02(1).
2. Whether Wis. Stat. § 31.02(1) authorizes the DNR to consider impacts on non-navigable wetlands and other non-navigable resources, and on adjacent property, when setting water levels for a navigable waterbody.
3. Whether the DNR may consider wetland water-quality standards in Wis. Admin. Code ch. NR 103 in a water-level proceeding under § 31.02(1).
4. Whether Wisconsin’s constitutional public-trust doctrine extends to non-navigable, private wetlands adjacent to navigable waters.
5. Whether the DNR committed legal error by excluding or giving no weight to economic-impact evidence that § 31.02(1) makes relevant.

## Decision

- The Wisconsin Supreme Court reversed the court of appeals and remanded to the DNR for further proceedings.
- The Court reviewed the scope of the DNR’s authority under § 31.02(1) de novo, rejecting great-weight and due-weight deference on the statutory questions presented.
- The Court held the DNR has broad statutory authority under § 31.02(1) to consider impacts on non-navigable wetlands and other non-navigable resources, and to consider effects on adjacent property, when setting water levels.
- The Court held the DNR may consider NR 103 wetland standards in water-level determinations affecting wetlands, but must weigh those standards within § 31.02(1)’s multi-factor framework rather than treating them as controlling on their own.
- The Court held the constitutional public-trust doctrine is limited to navigable waters and does not, by itself, extend to non-navigable private wetlands above the ordinary high-water mark.
- The Court held the DNR erroneously excluded most economic-impact testimony and must consider such evidence as part of the statutory balancing required by § 31.02(1).

## Legal Principles

- Determining the scope of an agency’s statutory power is a question of law for the courts; absent a long-standing, consistent agency interpretation, courts apply de novo review.
- Wis. Stat. § 31.02(1) authorizes the DNR to set water levels in the interest of public rights in navigable waters and in the interest of life, health, property, and public welfare; this permits consideration of impacts on adjacent non-navigable wetlands and adjacent property.
- The public-trust doctrine under Wis. Const. art. IX, § 1 applies to navigable waters and associated public rights, and does not constitutionally reach private, non-navigable wetlands above the ordinary high-water mark.
- The legislature may authorize regulation protecting non-navigable wetlands and uplands affecting navigable waters through statute, independent of constitutional public-trust limits.
- In § 31.02(1) water-level decisions, the DNR must conduct a multi-factor analysis that includes environmental, navigational, and economic considerations; excluding relevant economic evidence is legal error.
- Administrative wetland standards (NR 103) may inform a § 31.02(1) decision when wetlands are affected, but must be integrated with the statute’s balancing of factors.

## Conclusion

The court held that while the constitutional public-trust doctrine is confined to navigable waters, the DNR’s statutory authority under Wis. Stat. § 31.02(1) allows consideration of non-navigable wetlands and adjacent property when setting water levels; because the DNR largely excluded economic-impact evidence required for the statutory balancing, the denial of the petition was reversed and remanded for reconsideration.


Rock-Koshkonong Lake Dist. v. Wis. Dep't of Nat. Res., 833 N.W.2d 800 (Wis. 2013)