Introduction As water resource problems increase in complexity, the present state of having uncoordinated and mission-driven water resources agendas among various stakeholders will have to change to address the many and complicated water supply and demand issues associated with climate change, population growth and the energy/water nexus. Institutional barriers to problem solution are often encapsulated in the term, "silos" and the way to bridge "silos" is through trans/interdisciplinary approaches. However, silos exist at many levels in hierarchical scales and have vertical and horizontal components of complexity. Here we examine the empirical structure underlying bridging complexity in water resources at different three scales using Texas, USA, examples: 1) Senate Bill 3, a state-wide process to set environmental flow protection standards. 2) SB3 Nueces River and Corpus Christi and Baffin Bays Basin and Bay Area Stakeholder Committee and Expert Science Team and 3) the Upper Llano River Watershed Protection Plan.
Methods The SB3 Environmental Flows Allocation Process attempts to address three key issues: * how much water is needed (and when it is needed) to keep the state's rivers and coastal estuaries healthy, * how much of that needed water, if available, should be protected as new water rights to withdraw water are issued, and, * if water needed for healthy rivers and estuaries is not currently available, how do we go about making it available so we can pass a healthy natural heritage along to future generations of Texans. The 80th Texas Legislature established the SB process to determine environmental flow standards for all major rivers and bay systems in Texas. Senate Bill 3 was designed to be an accelerated, stakeholder-driven, scientific and consensus-based process to establish environmental flow recommendations. The new law establishes a process for determining how much water is needed for the environment. Each river/bay system has a team of stakeholders from diverse interest groups and a science team. The science team makes recommendations for flow quantities based on best available science; the stakeholder group examines science recommendations in conjunction with water management policies to develop their own recommendations. The Texas Commission on Environmental Quality considers both science and stakeholder group recommendations, and public input, and adopts formal environmental flow standards-goals for amount of flows in rivers and associated bay systems. Second, we describe the collaborative, consensus based process used by the SB3 Nueces River expert science team to determine a "sound ecological environment" in relation to the environmental flows analysis incorporating spatial and temporal variability that sustains native species, habitats and ecosystem services. Third, to manage and maintain the ecological integrity of the Upper Llano River,Texas using a partnership approach, the Texas Tech University Llano River Field Station, Texas A&M Water Resources Institute, Texas Parks and Wildlife Department are working with the South Llano Watershed Alliance to develop and implement a Healthy Watershed Protection Plan (WPP) through a federal Clean Water Act 319(h) grant from the Texas State Soil and Water Conservation Board and U.S. Environmental Protection Agency. We characterize complexity of the watershed ecosystem through an integrated assessment of the landscape and biotic condition; abiotic parameters, critical watershed functional attributes and water yield from implementation of best management practices (BMP). The WPP uses a stakeholder process for decision-making on issues; economics of BMPs; landowner concerns; types of treatment measures needed/recommended; and implementation. Watershed education includes public workshops and curriculum for K-12 students. Agency partnerships, stakeholder/landowner involvement and education are considered resistance and resilience components of watersheds that promote stability by increasing capacity to absorb disturbances. The pristine nature of the watershed and flow from springs support a unique ecosystem and provide constant critical flows downstream to the Colorado River and Highland Lakes/Austin, especially during drought. However, aquifer withdrawals, invasive species encroachment, and loss of riparian habitat threaten the health of the watershed and have many ramifications downstream. Here, we focus on 3 factors with strong downstream impacts: 1) loss of riparian habitat (invasive herbivores), 2) invasive hydrophytes and 3) brush control. We used hydrologic models (EDYS) to simulate changes in stream flow caused by removal of invasive vegetation.
Results Seven of eight river and bay systems of Texas now have instream and freshwater inflow recommendations, the Corpus Christi/Baffin Bay of the Nueces River was the only estuary system deemed not a "sound ecological environment" due to reduced historical freshwater inflows from reservoir construction and development and the Upper Llano Watershed Protection plan has an assessment of the watershed and a set of best management practices to address insipient threats to water quantity and quality and a better educated and proactive set of stakeholders.
Conclusions Integrated, proactive, scale appropriate, system based science and policy analysis of major rivers and connected estuaries and upstream watershed management can be effective tools in addressing mechanisms of stream ecosystem impairment in mitigating water quantity and biological pollution impacts on downstream urban stream ecosystems. The success of these three projects show how ongoing work at the academic, federal, state and local levels that are embracing new and novel paradigms for managing complexity and bridging silos in which multiple water resource areas are brought together to balance the competing and complementary goals of ecosystem health, productivity, economic and social well-being.