Facts
The appellant is the owner of two parcels (Nos. 182 and 183) in the municipality of Himmelried. The parcels lie in the agricultural zone and are overlaid by the Jura protection zone. On parcel No. 183 he erected, without a building permit, several small structures, retaining walls and an artificial shallow-water pond (20 x 8 m) with surrounding gravel areas, as well as a Stellriemen.
The Department of Construction and Justice of the Canton of Solothurn (BJD) examined the subsequent building application and conducted an on-site inspection in November 2014. By decision of 9 November 2017 it retroactively approved part of the structures. It refused approval for the retaining walls, the shallow-water pond with gravel areas and the Stellriemen. It ordered their removal or restoration of the original condition and instructed the municipality to monitor compliance.
The Administrative Court of the Canton of Solothurn upheld the decision by judgment of 19 November 2018 (VWBES.2018.66). The appellant lodged an appeal under public law with the Federal Supreme Court. He requested subsequent building approval, alternatively remittal, and in the further alternative an extension of the dismantling deadline to 30 November 2020. By presidential order of 3 April 2019 the Federal Supreme Court granted suspensive effect to the appeal.
Disputed are the establishment of facts, the right to be heard (rejection of evidentiary requests), permissibility of approval under Art. 24c SPA, and the proportionality of the dismantling.
Considerations
The appeal against the final cantonal decision in building law was admitted (Art. 82 et seq. FSCA, Art. 89 para. 1 FSCA). The requests to annul dispositive paragraphs 3, 6 and 7 of the BJD decision were not admitted, as they were replaced by the judgment of the lower instance (devolutive effect). The complaint regarding the facts was dismissed: the Federal Supreme Court bases its review on the facts established by the lower court (Art. 105 para. 1 FSCA) and only examines complaints raised clearly and in detail. The failure to mention the structures approved in 1962 and since removed was not relevant, as only the newly erected structures were to be assessed and there was no protection of existing status.
The complaint of violation of the right to be heard (Art. 29 para. 2 Cst.) was also rejected. The court may reject evidentiary requests if the facts are already sufficiently documented and it may, in anticipatory assessment of evidence and without arbitrariness, assume that further evidence would not change anything. The lower court permissibly relied on plans, the building application, on-site photographs, a letter from the landscape architect and map services. That the appellant could not comment again before the dismissive decision was not objectionable.
On permissibility under Art. 24c SPA in conjunction with Art. 42 SPO: the structures are not in conformity with the zone and are not site-bound. Changes to structures non-conforming to the zone are only permissible if the identity of the structure, including its surroundings, is preserved in its essential features, which requires a balancing of interests. The artificially created pond and the terracing through the retaining walls significantly impair the landscape and are atypical for the surroundings; the rural character is lost. Removing old elements (children's swimming pool, concrete slab, staircase) does not change this. Moreover, the installation does not meet the requirements of § 24 para. 1 NCHO/SO regarding particular consideration of the built environment and landscape.
On proportionality of the dismantling (Art. 36 Cst.): restoring the lawful condition is in principle required to maintain the separation of building and non-building zones and not to reward unlawful conduct (BGE 136 II 359). This also applies to smaller structures, to…