The session prior was focused on aquifers and the current and escalating condition of water insecurity. Given that as a beginning, this session will address one of the base principles of design: all design is dealing with opportunities and constraints. In regards to stormwater management as Landscape Architects we must consider how to turn the constraint of accelerating stormwater challenges into opportunities in design. This presentation is a distilled version on the stormwater course I teach at the University of Wisconsin-Madison, and as such, will connect some elements quickly which deserve greater time in class.
In city evolution we are seeing a “densification” in population. This is a trend identified by the UN at Habitat Three. We often speak of sustainable development. How can this apply to cities? Concentrations of humans in a small space equals accelerated use of the resources. In Ecology we learn the term “carrying capacity.” Cities have exceeded their carrying capacities by far. We hear about “food deserts” in cities. We must also consider where the water is coming from. These issues must be accounted for by city design. Infrastructure must include water and food production for a truly sustainable city design.
We will talk about the dual components of stormwater: quantity and quality. The quantity is quantifiable with some ease, while the quality is very specific to site considerations. The Rational Runoff formula is the basis for stormwater modeling. We will reconnect with that simple formula with new perspective in light of a changing climate. This will give a quick oversight into the quantity portion of the equation noted above. Again, we must remember that the rate of stormwater increase is logarithmic, and that, alone should give pause to anyone dealing with stormwater management.
Next we will examine the quality issue of stormwater. We will discuss sediment sequestration and why it is critical to any project, any scale, and any site. Next we will look (briefly) at acid rain (it is ubiquitous and never went away), and the implications that presents to our aquifers and aquacludes. We will note agricultural runoff and site specific responses via bio-activated swales, etc, to deal with some pollutants. We will also discuss the common sources of failure to planted depressions often called rain gardens. We will quickly discuss phyto-remediation techniques in the landscape, including floating islands.
We will briefly talk about the necessary consideration of alternate use of gray water for uses that are now being served by potable water. This will quickly cover flushing toilets, cooling building mechanicals, and geothermal considerations.

Learning objectives:

1. Better understand the quote from G. Box, “All models are wrong. Some are useful.”
2. You must consider the assumptions made in any modeling strategy, and account for the potential critical issues that those assumptions affect. In regard to stormwater, these can be disastrous.
3. Sequential treatment of both quantity and quality of stormwater runoff must be considered in any design.
4. A reminder that you, as a Landscape Architect, by the LAAB guidelines for accredited programs in the Profession, have more education in stormwater than Civil Engineers. There are also questions on the LARE about stormwater, which do not occur on the Civil Engineer’s licensing examinations. You are responsible for the health, safety, and welfare of your clients, and those who will be impacted by your work on any site.