Landscape and Urban Planning 144 (2015) 74–89 Contents lists available at ScienceDirect Landscape and Urban Planning j o ur na l ho me pag e: www.elsevier.com/locate/landurbplan Research paper A scenario-based approach to integrating flow-ecology research with watershed development planning Hong Wu a , John P. Bolte b , David Hulse a , Bart R. Johnson a,∗ a Department of Landscape Architecture, University of Oregon, Eugene, OR 97403, USA b Department of Biological & Ecological Engineering, Oregon State University, Corvallis, OR 97331, USA h i g h l i g h t s • We simulate four development scenarios with an agent-based landscape change model. • We evaluate scenario impacts with 10 ecologically significant flow metrics. • A flow metric sensitivity typology links flow alterations to plans of actions. • Integrated stormwater management (ISM) is crucial for reducing flow alterations. • Compact regional growth may be most important in the absence of ISM. a r t i c l e i n f o Article history: Received 24 February 2015 Received in revised form 11 August 2015 Accepted 16 August 2015 Available online 19 September 2015 Keywords: Alternative futures Land use change Hydrological impact Flow metric Regional growth pattern Integrated stormwater management a b s t r a c t The ability to anticipate urbanization impacts on streamflow regimes is critical to developing proactive strategies that protect aquatic ecosystems. We developed an interdisciplinary modeling framework to evaluate the effectiveness of integrated stormwater management (i.e., integration of strategic land-use organization with site-scale stormwater BMPs) or its absence, and two regional growth patterns for main- taining streamflow regimes. We applied a three-step sequence to three urbanizing catchment basins in Oregon, to: (1) simulate landscape change under four future development scenarios with the agent- based model Envision; (2) model resultant hydrological change using the Soil and Water Assessment Tool (SWAT); and (3) assess scenario impacts on streamflow regimes using 10 flow metrics that encom- pass all major flow components. Our results projected significant flow regime changes in all three basins. Urbanization impacts aligned closely with increases in flow regime flashiness and severity of extreme flow events. Most changes were associated with negative impacts on native aquatic organisms in the Pacific Northwest. Scenario comparisons highlighted the importance of integrated stormwater manage- ment for reducing flow alterations, and secondarily, compact growth. Based on a flow metric sensitivity typology, six flow metrics were insensitive to development in multiple basins, and four were sensitive to development and manageable with mitigation in multiple basins. Only three metrics were ever sensitive to development and resistant to mitigation, and only in one basin each. Our findings call for regional flow-ecology research that identifies the ecological significance of each flow metric, explores potential remedies for resistant ones and develops specific targets for manageable ones. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Urbanization has been an important driver of aquatic ecosys- tem degradation around the world (Miltner, White, & Yoder, 2004). The efficient routing of stormwater off large areas of urban ∗ Corresponding author. Tel.: +1 541 346 2235. E-mail addresses: wuhonguola@gmail.com (H. Wu), john.bolte@oregonstate.edu (J.P. Bolte), dhulse@uoregon.edu (D. Hulse), bartj@uoregon.edu (B.R. Johnson). impervious surfaces and into storm sewer systems results in fundamental changes to flow regimes of the downstream rivers and streams (Walsh, Fletcher, & Ladson, 2005). Despite extensive research, the complexity of the problem, insufficient analytical tools, and conflicts among socioeconomic forces have constrained the development of effective solutions that arrest stream degrada- tion. Anticipating the impacts of anthropogenic changes to rivers and streams is critical to developing proactive strategies to main- tain healthy aquatic ecosystems that, in the words of Meyer (1997) are “sustainable and resilient, maintaining (their) ecological struc- ture and function over time while continuing to meet societal needs and expectations”. http://dx.doi.org/10.1016/j.landurbplan.2015.08.012 0169-2046/© 2015 Elsevier B.V. All rights reserved.