National Stormwater Calculator

The U.S. Environmental Protection Agency

Overview: The U.S. Environmental Protection Agency is the federal organization that develops policies concerned with human health and the environment.

How to Use This Resource: This desktop application estimates the annual amount of rainwater and frequency of runoff from a specific site anywhere in the United States.

Year: | Source: | Risk: , | Region:

Extreme rain: New research predicts wetter, riskier storms for much of U.S.

By A. Adam Glenn

In the news: Extreme rains are expected to increase significantly across nearly the entire continental United States, according to a government study that provides a highly detailed picture of wetter storms to come with climate change. 

Back story: Researchers at the National Center for Atmospheric Research said in the Dec. 5 study that extreme precipitation can be expected to increase as much as five fold, especially in the Northeast and Gulf Coast regions. But even the Midwest, which is getting drier, will see intense rains that could cause serious erosion.  

Adaptation angle: The resulting rise in flash flood risk and challenges for existing infrastructure suggests “a clear need to increase societal resilience … and fundamental reassessments of planning approaches to intense precipitation, local flooding, landslides, and debris flows,” argued the authors. 

Questions to ask 

  • What specific changes in extreme precipitation events are expected in your area?  
  • What kinds of disruptions, such as landslides or erosion, can be expected as a result of heavier rains? 
  • How well prepared are local authorities for impacts from extreme weather and floods, such as power outages and transportation disruptions?  
  • Does your community have an early warning systems? 
  • What changes in area stormwater management might be needed to prepare for overflowing reservoirs or overtaxed sewage systems? 

Check for additional questions to ask in our backgrounder on inland flooding

Reporting resources 

Dig deeper on the extreme rains story using the dozens of related resources on storms and floods in the Reporter’s Guide to Climate Adaptation database. 

Know of other extreme precipitation resources we should include in our database? 

Posted by A. Adam Glenn on Dec. 15, 2016


Flooding in Texas – Is Your State Next? How to Cover Inland Flood Risk

IN THE NEWS: The torrential downpours that have swollen rivers in Texas in recent days, taking at least six lives, and heavy rains that inundated Houston earlier in April, costing eight lives and forcing the evacuation of thousands, are harbingers of rising inland flood risk, not just in Texas and the Southwest, but through the country.

BACKSTORY: Experts in a federal study warn extreme rain is increasing nationally, especially in the Northeast, Midwest and upper Great Plains, and that flooding may intensify in many regions of the country. Flash floods and urban flooding linked to heavy rain are also expected to increase.

ADAPTATION ANGLE: But many states aren’t prepared for the rising risk. According to an analysis of more than 30 states, half have taken no action to plan for future changes in inland flooding risks or implemented strategies to address them. Among those receiving especially poor grades are Arkansas, Florida, Illinois, Kansas, Missouri, Ohio, Oklahoma, South Dakota, Tennessee and West Virginia.


  • What’s the risk in your region, and how well are authorities prepared?
  • What early warning systems are in place, including for inundated roads where most of the fatalities in Texas have taken place?
  • How well is your area prepared for the power outages, transportation problems and other impacts that can come with flooding?
  • What are the risks to other infrastructure, such as water treatment facilities?
  • What are the risks of local flood waters carrying toxins or other health hazards?
  • What procedures are in place for local dams to help with flood control?
  • How well are emergency responders prepared for floods and flood rescues?
  • What can residents do to better prepare and be safe during floods?
  • Are rising flood insurance costs an issue locally?

REPORTING RESOURCES: Dig deeper on the flood risk and response story using the more than three dozen flood-related resources in the database of the Reporter’s Guide to Climate Adaptation:

Posted by A. Adam Glenn on June 6, 2016