Prairie Hydrology, Flood Modelling and GIS

Transcription

1 Prairie Hydrology, Flood Modelling and GIS Saskatoon, March 20 21, 2012 Meeting Notes Summary of Prairie Hydrology, Flood Modelling and GIS Meeting This document provides a summary of the key outcomes, presentation highlights, general discussions (and table of presenters and topics) from a meeting that was held at the Agriculture and Agri-Food Canada (AAFC) Research station in Saskatoon, SK on March The meeting was organized by several employees of the Agri-Environment Services Branch, AESB (Gord Bell, Cam Kayter, Erl Svendsen) and an NSERC Visiting Fellow (Robert Armstrong) working with AESB on climate variability and climate indices in support of agricultural production, and terrain analysis techniques. There was a great deal of interest in this meeting and the various presentation topics. We are grateful to all the organizations and individuals that prepared materials and gave presentations. We certainly hope this was the first of such meetings in the future, and we regret we were unable to accommodate all interested individuals and organizations due to logistical constraints. Key Outcomes: 1. Submission of a 1 page information sheet on each group s technical expertise in the following categories: Climate, hydrology and hydraulics, and useful products that can be produced by each group (now and possibly in the future); suggested by Gord Bell and a template has been generated and sent out as a reference for others to create their own. 2. Establishment of a Wiki Page as a potentially practical and efficient resource base for organizing a Community of Practice; suggested by Robert Armstrong - MESH Modelling community wiki page maintained by Bruce Davison (EC) cited as an example. With help from Kevin Shook the page construction has been initiated. Currently Kevin Shook and Robert Armstrong are Admins for the page construction. We greatly appreciate everyone s patience until the page is in decent shape to be rolled-out. 3. Identify other potential community members who might benefit and/or contribute to a Prairie Hydrology Community of Practice; thanks to Jim Yarotski for the reminder! 4. Howard Wheater suggested a centralized focus on Saskatchewan is needed to start. Essentially our focus will be to try and get this up and running for Saskatchewan and do it well. Hopefully those in Alberta and Manitoba (and beyond) might take an interest and organize something similar.

2 Food For Thought from Presentations Gaps still exist between Researchers, Practitioners and End Users communities. Research tools often lack support and training outside of the research sphere. o What s required is support or a community plus a forum for discussion and information storage/dissemination. Also at issue is that researchers and practitioners do not often work together and work essentially in silos o Other silos also exist: Land & water users/decision makers Policy makers o Researchers require accurate data; Decision makers don t need more data they need information or an answer to the question: What kind of policies/decisions will make a positive impact on the landscape. Open source tools both powerful and flexible; limited development opportunities within research sphere without collaboration from potential users and other developers. Open MI ( provides framework for linking different models. Flood Damage Reduction Program (1980 s) forgotten resource? consisted of federal standardized hydraulic studies associated with river reaches to determine flood levels that might impact populated locations (e.g. cities or towns); developed from aerial photos; flood profiles mapped onto topographic maps o In SK, it was a collaborative project between SK-Env and EC. There were prescriptive procedure manuals and this was a highly scrutinized project. o EC later pulled out, leaving the province to proceed alone. o A case study of Swift Current produced the following outputs: Flood hazard maps Hydrology study Hydraulic study Mitigation study o One of the criticisms of the project was that a risk-based assessment cannot be conducted using event-based hydrologic (precipitation runoff) modelling analysis. 1:100 runoff event does not necessarily result from the 1:100 precipitation (depth) event. Model parameter calibrations time consuming and may not transfer well to other basins. Cold Regions Hydrological Model (CRHM) platform currently the only tool with the capacity for assembling hydrological models relevant for prairie hydrology conditions; considers snow processes and wetland/pothole fill and spill theory; does not allow for explicit geospatial modelling at this point; Challenges climate change, adaptation options; real time human intervention during flood events. SWAT model allows for hydrology and economic simulations; GIS interface integrates economics; snow redistribution and frozen soils now included; does not address fill and spill hydrology at this point. Telemac 2-D flood modelling at Lower Pembina River (Canada/U.S. Border) allowed for visualization of inundation areas along river reaches; results also showed the inability to completely remove water from a drainage system; there were always winners and losers under different drainage (e.g. dykes, diversions) and retention strategies; road networks both beneficial as dams but also present a limitation for adaptations.

3 Environment Canada has outputs that may be useful for practitioners (e.g. precip fields, SWE and soil moisture fields; areas potentially at risk to flooding - regional scale). Remote sensing via optical and microwave frequencies are useful for examining spring runoff events; RADARSAT has difficulties and challenges due to scattering effects from wet soils and dense vegetation; RapidEye optical sensors offer much more technical accuracy but limited during cloud cover; capacity to observe which ponds fill and spill to other wetlands and those that do not; DUC Smith Creek data can be viewed at: Challenges for Ministry of Sask Highways: Accurate discharges, Q needed at culverts; delineation of basin area contributing to culvert; concerned with accuracy of Q estimates and would like to investigate more accurate methods of obtaining Q under Prairie hydrological conditions. Rural Municipalities interested in LIRA type methodologies to examine flood vulnerability and economic cost-benefits associated with different adaptations (e.g. SWA expanding on previous LIRA work in North Corman Park area) o The success of LIRA in the NCP area was the development of information that could be used to support development and mitigation decisions based on economic factors. o The challenges of the LIRA process are: Each study area is unique requires customized analysis (but based on a standard methodology) High quality topographic data required for a geospatial analysis (flood modelling) in short supply; requires decision-analysis support Complicated simulation models not used to predict current-year flood potential; instead uses data from a proxy year matched to current conditions to predict near-future flood potential o SWA reviews recent climate information (e.g. melt rates, snow-water equivalents, snow surveys, fall conditions, etc) and tries to find a match in the past to predict what will occur in the near future regarding flood potential. o Challenge: regional scale analysis, does not necessarily provide community level decision support. o Challenge: difficulties in addressing anomalous conditions e.g. 2011: wet fall, heavy winter snow fall, wet spring = no proxy years. Global Institute for Water Security developing flood risk analysis at scales in the order of 10 km to 45 km for Canadian Prairie basins based on previous work applied in Quebec; investigating changes in extreme precipitation; also investigating use of multiple RCM ensembles which can provide information on upper and lower limits of model predictions (includes European, U.S. and Canadian RCMs); single site models capable of providing patterns of rainfall; continuous time series of rainfall from generalized linear models applicable for flood risk assessment; capacity for temporal downscaling; future goals include spatial modelling and variability of precipitation (e.g. storm cell arrival and movement, frontal precipitation). Some common threads among presentations: regardless of approach there is always uncertainty in model results; increasing need for high resolution elevation data

4 o A reasonability test needs to be applied to model outputs where validation data is lacking. That is, do the outputs make sense to end users with local knowledge? Do outputs agree with on-the-ground observations? o If not, then need to go back and reconsider assumptions and/or methods. Discussion Summary Several questions were proposed at the beginning of the meeting in order to generate a practical discussion. 1. Are current approaches sufficient to address modelling and planning requirements? 2. Where are the gaps and where do we need improvements? 3. Where might integration be possible? 4. Group discussion of capacity to lead or participate in modelling projects? 5. Creating a resource of links for networking and modelling tools and input/output sharing towards the development of Community of Practice. During the discussion it became clear that the questions were not necessarily independent and discussion points generally overlapped; addressing several questions at once in some cases. Also, the group agreed that it would be useful to have a one or two page synopsis of mandates, expertise and modelling strengths by each group and also for others that were not in attendance (e.g. NRCan, SRC, U of R etc.) Noteworthy discussion from Question 1. Theoretical approaches and model developments may never be sufficient to address all the modelling and planning requirements. No single model has been developed yet that integrates all the appropriate physical processes for prairie hydrology and explicitly considers the spatial associations and connectivity of real world landscape features, and can consider investigations of best management practices. Currently the Cold Regions Hydrological Model (CRHM) platform is the only tool with the capacity for assembling hydrological models that includes Canadian prairie hydrological processes (e.g. snow processes and, fill and spill); different from watershed models that explicitly require the inclusion of a permanent stream channel based on DEM basin delineation techniques. Researchers and practitioners starting to bridge gap to increase modelling capacity. WEBS groups are also working together on various projects. Noteworthy discussion from Questions 2 and 3. A key (and historical) gap identified by the group remains between researchers and operational communities. This seems to be directly tied to differences in mandates of the respective groups. Researchers develop projects around a pressing question to gain a better understanding of important interactions and modelling requirements. The operational group requires tools for decision making or forecasting over a given time frame. The challenge is in better integration and collaboration between research and operations. Environment Canada has begun to integrate

5 CRHM for the hydrological modelling component within the MESH forecasting system. AESB is in a good position to be more flexible and open to new and improved modelling strategies. A practical integration would be possible in LIRA by using outputs from one modelling component as input to another modelling component. Specifically, using runoff outputs obtained from CRHM as input for the spatial runoff modelling component to provide the distribution of water over the entire landscape. Also, the global institute s future work will include spatial modelling of storm events that may be useful for spatial modelling of the fate of runoff across the landscape. Potential limitations in the internal analytical (i.e. hydrologic modelling) capacity for LIRA projects means relying on external expertise and contractor to conduct work. However, consultants may rely on their own methodology and experience. The problem is that the methodology and experience may not be relevant in the prairie environment. Several questions arise: - How do you manage consultants with different levels of ability? - How do you move the information back to other organizations? - How dependable is their output? - How prescriptive can the hiring organization be when defining the scope of work? Along with losing capacity is the shortfall in opportunities to continue professional training for both new [young] and established professionals. Definitely one gap just at this meeting is that an entire group of practitioners were not represented: private consultants. Maybe not appropriate to have been included here, but still an important segment that needs to be brought into the general discussion at some point. Also, not a lot of end-users present at meeting. They are the beneficiaries of model development and output. From their perspective, model outputs are useless to them if they are unable to make decision (planning, mitigation, compensation, etc.) with the information. So there is a need to work with end-users to: 1. Identify needs and research questions and to then 2. Identify or develop research tools to solve the problems. Noteworthy discussion from Question 4. The potential capacity of a particular group to lead modelling projects was again tied to specific mandates. It would be beyond the scope of any group to lead a specific modelling project and organize the collaboration of the other groups to be involved that fell outside of their particular mandate. For example, operational modelling tends not to be needed for answering research questions. The end user groups tend to be the forgotten community when it comes to research and operational problems. The focus tends to be on answering specific questions driving research or operational needs. The end user groups are rarely integrated into the process to find out what information may be useful to them and then developing research projects specifically designed to develop tools for those needs. More than likely there might be inherent challenges and some interesting research questions that emerge along the way. More often than not research and operational uses are

6 tailored to what we can handle well and more difficult problems tend to be ignored due to time constraints. Noteworthy discussion from Question 5. The meeting was designed to begin a dialogue among the various participants as a first step to forming a Community of Practice that focused on hydrological and flood modelling related issues in the Prairie Region; more specifically with a Saskatchewan focus in this case. It was quickly discovered that due to differences in mandates that no single group had the capacity to lead the development of a Community of Practice through a resource of links. Such a task might be better suited for a core of dedicated individuals to lay the ground work for building a Community of Practice. Robert Armstrong indicated he would start laying the foundation to achieve this goal. The group showed interest in the development of a Wiki page that contained information on the mandates and capacities of various organizations to be involved, provide expertise, and carry out work on various modelling problems. The Wiki page can serve as a Community of Practice forum, a central distribution area for information, links and news, and an area for sharing expert knowledge on a variety of important topics related to hydrology, flood modelling and GIS within Saskatchewan. Robert Armstrong indicated he would start the development of such a Wiki resource with the help of Kevin Shook who could provide access to the U of S resource. The Wiki would include links to the various organizations that are involved in research and operations, and that can provide relevant technical guidance. It would also be useful within the Community to have pages dedicated to providing overviews of technically challenging topics and decision-tree type support and important considerations for particular modelling problems and open source resources for data manipulation and geospatial analysis.

7 List of Presenters and Topics Presenters (in order) Organization Topic Kevin Shook Centre for Hydrology, U of S Complexity of Prairie Hydrology Anthony Liu Environment Canada Summer Flooding on the Prairies: a climatological and numerical study Curtis Hallborg SWA 2011 Southern Saskatchewan Flood Overview Ron Woodvine AESB Federal Disaster Reduction Plan work in the 1980s Brian Bell AESB Probable Maximum Flood analysis for Shellmouth Dam on Assiniboine River in Manitoba Jim Yarotski AESB SWAT Modelling and future improvements Gord Bell AESB Lower Pembina River flood Modelling using TELEMAC Bruce Davison Cherie Westbrook Lyle Boychuck Doug Ross Doug Johnson Robert Armstrong Naveed Khaliq Howard Wheater Environment Canada Centre for Hydrology, U of S Ducks Unlimited Canada Ministry of Sask Highways SWA AESB Global Institute for Water Security Global Institute for Water Security Exploring R&D opportunities for flood forecasting using EC's forecasting system Prairie hydrology Modelling at Smith Creek Use of multi-temporal fine-quad polarimetric imagery to monitor spring runoff events Challenges for design flows and assessing vulnerability for the Ministry of Highways and Infrastructure Corman Park and Area Regional Water Management Plan Land and Infrastructure Resiliency Assessment (LIRA): Economic Flood Hazard Assessment Extreme precipitation and flood risk analysis using dynamical downscaling and regional frequency analysis approach New approaches to flood risk management for a changing climate: climate downscaling, continuous simulation Modelling and vulnerability analysis

8 Appendix A Meeting Genesis The initial idea for the meeting originated from a discussion between Cam Kayter and Robert Armstrong regarding the flood hazard assessment modelling requirements for the Land and Infrastructure Resiliency Assessment (LIRA) project; a sub-component of AESB s Climate Adaptation for Resilience in Agriculture (CARA) project. Issues regarding the uniqueness of Canadian Prairie hydrology compared to standard river basin modelling practices were a main concern. Dr. John Pomeroy (Centre for Hydrology, U of S), Brenda Toth (Environment Canada) and Gord Bell (AESB) were then consulted regarding interest in having an internal meeting on the topics of Canadian Prairie hydrology, the current state of flood modelling practices and the needs for the LIRA project. One of the benefits was to bring the research and operational communities together to discuss current issues and ways to bridge the general gap between these groups. These discussions suggested there would be a great deal of interest in an information sharing meeting and might also be of interest for a wider audience, specifically with a Saskatchewan focus. For logistical reasons and in the interest of keeping the group relatively focused several individuals were approached to give presentations on Prairie hydrology, flood modelling and GIS techniques. The presentations included past, present and future modelling practices. Brief Background to the Land and Infrastructure Resiliency Assessment (LIRA) Project The goal of LIRA is to provide decision makers at the watershed scale with the integrated physical tools and analysis techniques to make better economic decisions related to a watershed s climate vulnerability and potential adaptation options. At the core, LIRA provides decision makers with an economic cost-benefit study that is spatially driven via flood hazard assessment tools; but may also have implications for drought adaptation in the future. LIRA is also developing a how to guide for future pilot sites based on a detailed methodology to support a transition of this technology to operational environments. LIRA has the capacity to be a fully integrated approach that requires physical, social and economic information. From a physical modelling standpoint, LIRA has the potential to bring together several distinct modelling components; 1. Prairie hydrological modelling (quantitative runoff outputs), 2. 2-D hydraulic modelling (inundation associated with channels), and 3. Explicit geospatial runoff modelling (fate of runoff across the landscape).