Month: January 2026

Sloped Green Roofs

Sloped Green Roofs

Sloped Green Roofs

01/09/26

“What are the advantages and disadvantages of sloping a green roof?”

Green roofs integrate stormwater management, biodiversity, building insulation, and aesthetic design all into one package. We can also pitch these green roofs at a slight angle to make Sloped Green Roofs. Sloped green roofs reduce ponding and may improve aesthetic appearance, but are also structurally and hydrologically more complicated. Stormwater runs off more from sloped green roofs, meaning roof plants may have to rely on other sources of water. 

Saturation Pressure

Saturation Pressure

Saturation Pressure

01/08/26

“What is the pressure at which a substance’s liquid and vapor phases are balanced with each other?”

Vapors form when molecules from a liquid bounce into the air as gases. At some pressures, more molecules escape, and at others, more return. The pressure where the molecular exchange between each phase is equal is known as the Saturation Pressure. The saturation pressure is dependent on temperature, since higher temperatures mean more molecules escape, necessitating a higher pressure to keep them contained. Saturation pressure dictates what the vapor makeup of a mixture will appear according to Raoult’s law.

Raoult’s Law

Raoult’s Law

Raoult’s Law

01/07/26

“How can we determine the vapor content of a mixture?”

Vapors form above liquids. When two liquids mix, their vapor will also be a mixture. Raoult’s Law describes the content of the vapor mix, with each component proportional to the percentage makeup of the liquid multiplied by its saturation pressure. If a component has a high enough saturation pressure, then it can have a larger presence in the vapour compared to the liquid.    

Soil Slope Toe

Soil Slope Toe

Soil Slope Toe

01/06/26

“What defines the base of a soil slope?”

Construction sites often have sloping soil mounds. The bottom section with a gentle slope that meets the ground is known as the Soil Slope Toe. The soil slope toe is important because it often experiences the highest stress and is where erosion concentrates.

Minimum Vertical Separation From Water Table

Minimum Vertical Separation From Water Table

Minimum Vertical Separation From Water Table

01/05/26

“Why do some engineering systems require a minimum vertical separation from the water table?”

Engineering systems may store water beneath the surface, such as septic systems for wastewater or infiltration systems for stormwater. However, these systems can cause catastrophic damage if they’re built too close to the water table. Septic systems can leach wastewater and contaminate groundwater supplies, while water infiltration can raise the water table and lead to flooding. Consequentially, government regulations may require a Minimum Vertical Separation From Water Table to ensure public safety. For example, the NYC Department of Environmental Protection mandates that stormwater infiltration practices in Brooklyn and Queens are at least 4 feet above the groundwater table.

Image credit: https://michigansaves.org/

Builders Pavement Plans

Builders Pavement Plans

Builders Pavement Plans

01/04/25

“What regulations do you have to follow if you install or alter curbs, sidewalks, or roadways in NYC?”

Different municipalities have different regulations for different construction activities. In NYC, people who install or alter curbs, sidewalks, or roadways are required to submit a Builders Pavement Plan, or BPP. The builders pavement plan documents what actions the construction operator is taking to install/alter their right-of-way infrastructure and how they will follow regulations. The NYC Department of Buildings reviews BPP applications and analyzes how they comply with city construction codes and NYC Department of Transportation rules, regulations, and standards. BPPs help ensure NYC’s urban planning stays strong and that city residents are offered a safe environment.

Common Plan of Development

Common Plan of Development

Common Plan of Development

01/03/26

“How can we build a large project in multiple distinct phases?”

Large construction projects often need to comply with stringent size-based regulations. Developers might subvert this by breaking up a large project into multiple sub-projects. To prevent this, U.S. governmental regulatory authorities will define projects with the same owner/developer completed in the same larger development plan as part of a Common Plan of Development. Permits will use the acreage of the total common plan of development to ensure construction operators meet planning requirements, such as stormwater pollution prevention plans.

Right of Way Dedication

Right of Way Dedication

Right of Way Dedication

01/02/26

“How can property owners transfer their land to use for public infrastructure?”

Public infrastructure such as roads and canals often relies on access to a legal right of way. Without this, parts of a municipality might not be accessible to the general public. One way property owners can increase the amount of public right of way is through a Right of Way Dedication. This involves transferring land from the property owner to the government agency to use for infrastructure. Property owners might use right-of-way dedications as leverage in land-use negotiations with government agencies.

Drawdown Time (Detention Tanks)

Drawdown Time (Detention Tanks)

Drawdown Time (Detention Tanks)

01/01/26

“How long does it take for detention tanks to empty their stored water?”

Detention tanks hold stormwater and release it slowly over time to prevent flooding. The amount of time it takes to empty the detention tanks, also known as the Drawdown Time, is dependent on a variety of factors, such as the volume of filtration, orifice area, acceleration due to gravity, and maximum hydraulic head above the orifice centerline. Detention tank drawdown is vital for hydrological engineering calculations. 

image credit: https://www.polymaster.com.au/