How to take steps toward sustainability with local watercourse modelling

Mapping the fine details of watercourses throughout your entire community might sound a bit overwhelming. But if you’ve experienced flooding in recent years, or have concerns about water quality, you might be willing to do some extra work to better understand the paths water is most likely to follow, as well as what’s along those paths. Mapping these details will help stakeholders monitor conditions more efficiently, act faster when needed and better prevent serious problems. In this blog post, we’ll look at the benefits of modelling watercourses in fine detail as well as at resources to help you get started.

On this matter, I decided to leverage the expertise of my colleague Audrey Beaudoin-Arcand, technological solutions specialist at Esri Canada. Last September, she wrote a blog post introducing the question Why fine mapping of watercourses? This post included important details about LiDAR data that are publicly available for Québec local governments, the ArcGIS licenses you’ll need to model your local watershed and training resources to help you get started.

This time around, I asked Audrey to elaborate on the benefits of this kind of modelling for local governments, what steps to consider and what to do with this new tool once it’s ready to share.

Question 1: Audrey, mapping watercourses for an entire territory sounds like an impossible task for local governments. What are some important reasons for them to consider it?

Hydrous environments (such as water courses, lakes, wetlands, shores, coastlines and floodplains) all play an important ecological role and therefore need to be protected. Damaged and destroyed by urban development, agriculture, untreated wastewater discharges, poor management of rainwater and loss of natural habitats, they no longer have the capacity to provide humans with the ecological services that we need to flourish. For example, hydrous environments reduce the risk of flooding, filter water from lakes and rivers, recharge groundwater, provide habitat to wildlife, sequester carbon, and improve the quality of the landscape, among other things. The destruction of these hydrous environments has serious consequences.

If we increase our knowledge of these environments by mapping them, we increase our chances of being able to protect them and mitigate the consequences of losing the ecological services they provide to us. That loss would be really catastrophic.

As an example of what’s being done in Canada to reduce the negative effects of human development, the Province of Québec implemented a new act in 2021 that improves the conservation of wetlands and bodies of water. This act will not only improve wetland management, but also prevent net wetland loss across the province. This act gives the responsibility to create and maintain detailed mapping of these hydrous environments to local government as a tool for achieving sustainable development.

Question 2: Creating a 3D model sounds like a lot of work. What can local governments do to make this process as efficient as possible?

To lighten this process and make it as efficient as possible, I recommend three key steps.

First, search for data that are publicly available (for example, Ministry LiDAR data, Ducks Unlimited Canada detailed mapping of wetlands, and Ministry watercourse mapping) and learn to work with those data in ArcGIS.

Secondly, enrich those data with your own data, such as your local government data or data collected from the field. Don’t forget that you can use ArcGIS Field Maps to simplify your field data collection workflows. Then, centralize all your data in your ArcGIS system to ensure interoperability of your data, models, maps and apps.

Thirdly, perform the analysis that will provide the results you are looking for. Creating a hydrologic network can be tricky. Learn what you will need to factor in and which tools can help you do that in ArcGIS Pro.

Finally, don’t forget that your model is a living tool. You probably won’t get a perfect model on day one, but rather a starting point for a model that will evolve over time. As data comes in and is validated, the model will become a more accurate representation of reality. This is what I like to call getting a holistic view of your environment, whether it’s the built or natural environment.

Question 3: Once the watercourse model is ready, what can a local government do with it?

This tool will allow you to analyze, understand and prevent certain situations. This is called predictive analytics for everyone. You can get a holistic view of what goes on in your watershed. For example, you’ll be able to monitor the geographic factors that affect water quality or see what’s upstream of a culvert that causes a certain section of road to flood every year.

Make this information available in a web app for your stakeholders. Depending on the audience you want to target, you can choose who will have access to the web apps you build. As an example, stories made with ArcGIS StoryMaps are a great way to build a sense of belonging, so you can use them to inform the public about a special hydrous environment that needs protection. Sometimes, the information needs to be digested for informed decision making. In that case, you might use ArcGIS Dashboards to visually represent that information in an engaging and easy-to-read format.

You could also go a step further and consider using ArcGIS Insights, with its powerful analytical capabilities, to build a workbook of watershed data. You can neatly summarize your analyses in a compelling visual to be shared with others, such as this amazing example of an Insights workbook made to monitor the Grand River Watershed in Ontario.

All these great possibilities start with building your model. What’s really important to keep in mind is that the result will be a living tool that needs to be consistently fed and watered with fresh data to reach its maximum potential. But it’s worth the effort—with a tool like this, you’ll unlock all kinds of new monitoring capabilities to keep your area safe.

This post was translated to French and can be viewed here.