Mountain-to-sea ecological-resource management: Forested watersheds, coastal aquifers, and groundwater dependent ecosystems

•Optimal investment in watershed conservation capital is usually positive (non-zero).•Upstream watershed conservation supports protection of downstream GDEs.•Stricter safe minimum standards for the GDE necessitate more investment.•Optimal investment is lower when capital is more efficient at capturing recharge.•Growing water demand requires more investment in the optimal solution.