Complex sentence: Facilitated on the national level by the Carey act of 1894, arid land in Harney County was donated to the state for irrigation and settlement, but all water development efforts failed, and eventually all land claims filed under the reclamation legislation were abandoned or nullified.
Split into simpler sentences: Facilitated on the national level by the Carey act of 1894, arid land in Harney County was donated to the state for irrigation and settlement, but all water development efforts failed. Eventually all land claims filed under the reclamation legislation were abandoned or nullified.