Urban Environmental Quality and Landscape Structure in Arid Mountain Environment

Urban landscape structural analysis; focused on the remnant patch mosaic network as the component with closest interdependency with air and water related processes was undertaken to find and propose environmental planning suggestions.Assessments demonstrate that remnant patch mosaic network structure of Tehran is still restorable. With appropriate corrective measures based on the natural lay out of river valley corridor network it could function as a refuge network to improve urban environmental quality through compensation of the insufficient natural matrix connectivity. In terms of cost effectiveness landscape structural restoration in the north of Tehran has priority due to the presence of river valleys in a heterogeneous mosaic of large grain green patches and the added value of down stream positive impacts. Extension of urban forestry in the south with an added value of increased sink capacity for assimilation of accumulated polluted waste water and air pollution may be the next priority regarding remnant open and green patch mosaic restoration. Restoration is harder to achieve in the central parts of Tehran with small grain homogeneous mosaic. The "Refuge network" based on natural layout of river valleys along with core open patches of hills may be the conceptual framework to integrate various corrective measures. The "Aggregate with outlier" model can provide the spatial design framework necessary for the implementation of such an integrated comprehensive remnant patch network restoration plan aimed at improving urban environmental quality.

Keywords
Urban landscape, Patch mosaic, River valleys, Metrics, Arid environment