Assessing Water Resource Demand in New York City

This page created by Kyle M. Monahan adapted from an original activity on NYC water supply losses along NYC aqueduct from Richard F. Bopp, Rensselaer Polytechnic Institute.
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Students are provided with current population growth data for New York City using recent (2010) US Census data from the Census FTP site: They use this data along with average values for water usage per capita in urban areas to create an assessment of the water demand of New York City. The students compare this assessment with the size of the catchment of the aquifer system, and estimate the flux of water via precipitation from three USGS gauging sites (from: near each watershed. This allows for the students to reconstruct the water flux into the known volume of water resources at NYC's disposal, and compare those values to water demand. Also provided are flow rates during previous drought events for NYC during 1980 and 1964 to assess the extent of previous water demand issues.

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Learning Goals

Concepts learned:
  • Water recharge, drainage basins and precipitation dynamics (from USGS data).
  • Population growth dynamics of New York City (from US Census data) as well as relation to resource demand.
  • Sustainability of water resources and fluctuation based on environmental changes; connections to an increase in population beyond carrying capacity of NYC's water resources, also Long Island with their dependence on their (increasingly polluted and salty) groundwater may be interested in using NYC water.
  • Conclusions can be drawn to more global water resources issues.
Skills learned:
  • data manipulation, usage of Excel
  • drawing conclusions from rather large datasets

Context for Use

This course worked best for small class sizes at the freshman-sophomore undergraduate level. Most of the work was done in class or right after class to help provide data visualization and manipulation tips for Excel. Office hours would be especially useful to make sure no students with very limited excel and data analysis experience are "left behind."

Description and Teaching Materials

  1. Set the stage with maps showing the path of New York City aqueduct along with the bounds of the city. Also provide background on why the water system is unique, why they provide limited water treatment, mention traditional water treatment in WWTPs.
  2. Show a graph of population growth in New York City.
  3. Next, have the students download first the data from the US Census FactFinder site: or the Census FTP site:
  4. Help the students graph the growth in population over time from 1900 - today and assess a growth rate.
  5. Now provide the students with average water usage per capita, so they can find the water demand for the current (2010) NYC population size.
  6. The students can now gather precipitation data for NYC across a given watershed from gauging stations (selection of specific gauging stations beforehand by site # speeds this activity up greatly, as USGS databases have a search function for specific site #). If the class size is amendable to it, it's good to split the watersheds for each aqueduct into groups, and gather the data together at the end.
  7. Finally, we now have assessed the flux of water into the water source. Provide the students with an estimate of the volume of water stored, and they can now assess risk of drought.

Teaching Notes and Tips

Notes: This is quite a long activity, 1hr +, but it is useful for getting students used to intense data analysis. Providing a Word document with links to data sites and screenshots along with step by step methods is very important.


The final product is an Excel spreadsheet with the data visualizations asked for in the Word document instructions sheet. Similarly, in another tab the students can answer questions which "get at" the engineering methods available to stabilize the water flow, predictions about changing water demand, as well as sustainability implications in a changing climate.

References and Resources