Thanks to all that joined or watched the Poolesville public hearing on the water supply. The full recording of the hearing is above.
The Town contractor’s 45 minute presentation highlighted differences in process and
conclusions with the research/reporting conducted by hydrogeologist Patrick Hammond. There are consequential differences in their respective methodology and emphasis as to how various factors affect groundwater availability in Poolesville. Mr. Hammond’s 15 minute power point presentation slides provides a history of the town’s municipal water supply and a summary of his report without commentary about the town contractor’s data and methodology. He did, however, provide some responses to the contractor’s presentation after the public meeting. A summary of those points with context follows.
Climate Change: a key difference in methodology
Background: The primary goal of the MCA groundwater study prepared by
hydrogeologist Pat Hammond is to employ current modeling/data to provide best information as to guide how collaboratively steward the sole source groundwater aquifer that supplies water to over a third of the county’s landmass – Montgomery County’s Agricultural Reserve, rural municipalities and edge communities. Mr. Hammond’s Maryland Department of the Environment (MDE) study “The Effect of Climate Change on Maryland’s Water Supplies” was the catalyst for our more locally focused study utilizing the solid water system record keeping of the town of Poolesville. Mr. Hammond’s published MDE study cites the Interstate Commission on the Potomac River Basin’s modeling on how climate change will affect regional water supplies.
The town hydrogeologist noted in her presentation that climate change is “complicated” and that the "MDE is not requiring municipalities to consider climate change in water management at this time due to uncertainty.” This contention, without reference documentation, seems at odds with State reports/literature.
Here are relevant MDE resources regarding recommendations for safeguarding water supplies to address climate change:
Here are relevant MDE resources regarding recommendations for safeguarding water supplies to address climate change. Here are the resources from UMD Extension.
The Interstate Commission on the Potomac River Basin (ICPRB) has conducted extensive modeling that forecasts climate change effect on regional water supplies. The WSSC has been working to put failsafe plans in effect to address these coming changes and any potential for water system disruption that will challenge their ability to meet water demand at various times. See press event from 2024
To be clear, while there are some data analysis differences between the two hydrogeologists, the primary substantive difference hinges on how we should account for the effects of a changing climate on water availability/well yields. Mr. Hammond notes that the town contractor in their reporting factored in an increase in future water use due to climate change based on 30 days of above 100 degree temperatures annually but then the town contractor used only 5 days of above 100 degree temperatures when analyzing the effect on well yields. Mr. Hammond’s report factors in 30 days of above 100 degree temperatures in the future to determine the effect (evapotranspiration etc.) on well yields. If we are to employ no regrets land use planning and decision making, this issue matters.
The Degradation of Horsepen Branch
Hydrogeologist Pat Hammond has raised important concerns that the Town’s continued reliance on a historically granted emergency overallocation (more than their permit allowed in a single watershed) to supply the population (at that point in time) with water has resulted in severe impairment of Horsepen Branch (flows south of Poolesville to the Potomac). Poolesville’s contractor did not address this issue. To date, the Town has not addressed the stream degradation or their continued reliance on the emergency over allocation as relates to future water consumption due to growth.
A town resident put it well in his questions after the presentation - if there is disagreement in the science and the Town's models say everything is fine and Mr. Hammond's models say we need to act quickly to avert serious issues- residents trust their leaders to take the prudent and conservative path that ensures resources remain abundant in the future. That path requires action.
For residents on wells - our recent webinar on well care is a great place to start learning about the aquifer and how to steward your own well for the future.
The Town contractor’s 45 minute presentation highlighted differences in process and
conclusions with the research/reporting conducted by hydrogeologist Patrick Hammond. There are consequential differences in their respective methodology and emphasis as to how various factors affect groundwater availability in Poolesville. Mr. Hammond’s 15 minute power point presentation slides provides a history of the town’s municipal water supply and a summary of his report without commentary about the town contractor’s data and methodology. He did, however, provide some responses to the contractor’s presentation after the public meeting. A summary of those points with context follows.
Climate Change: a key difference in methodology
Background: The primary goal of the MCA groundwater study prepared by
hydrogeologist Pat Hammond is to employ current modeling/data to provide best information as to guide how collaboratively steward the sole source groundwater aquifer that supplies water to over a third of the county’s landmass – Montgomery County’s Agricultural Reserve, rural municipalities and edge communities. Mr. Hammond’s Maryland Department of the Environment (MDE) study “The Effect of Climate Change on Maryland’s Water Supplies” was the catalyst for our more locally focused study utilizing the solid water system record keeping of the town of Poolesville. Mr. Hammond’s published MDE study cites the Interstate Commission on the Potomac River Basin’s modeling on how climate change will affect regional water supplies.
The town hydrogeologist noted in her presentation that climate change is “complicated” and that the "MDE is not requiring municipalities to consider climate change in water management at this time due to uncertainty.” This contention, without reference documentation, seems at odds with State reports/literature.
Here are relevant MDE resources regarding recommendations for safeguarding water supplies to address climate change:
Here are relevant MDE resources regarding recommendations for safeguarding water supplies to address climate change. Here are the resources from UMD Extension.
The Interstate Commission on the Potomac River Basin (ICPRB) has conducted extensive modeling that forecasts climate change effect on regional water supplies. The WSSC has been working to put failsafe plans in effect to address these coming changes and any potential for water system disruption that will challenge their ability to meet water demand at various times. See press event from 2024
To be clear, while there are some data analysis differences between the two hydrogeologists, the primary substantive difference hinges on how we should account for the effects of a changing climate on water availability/well yields. Mr. Hammond notes that the town contractor in their reporting factored in an increase in future water use due to climate change based on 30 days of above 100 degree temperatures annually but then the town contractor used only 5 days of above 100 degree temperatures when analyzing the effect on well yields. Mr. Hammond’s report factors in 30 days of above 100 degree temperatures in the future to determine the effect (evapotranspiration etc.) on well yields. If we are to employ no regrets land use planning and decision making, this issue matters.
The Degradation of Horsepen Branch
Hydrogeologist Pat Hammond has raised important concerns that the Town’s continued reliance on a historically granted emergency overallocation (more than their permit allowed in a single watershed) to supply the population (at that point in time) with water has resulted in severe impairment of Horsepen Branch (flows south of Poolesville to the Potomac). Poolesville’s contractor did not address this issue. To date, the Town has not addressed the stream degradation or their continued reliance on the emergency over allocation as relates to future water consumption due to growth.
A town resident put it well in his questions after the presentation - if there is disagreement in the science and the Town's models say everything is fine and Mr. Hammond's models say we need to act quickly to avert serious issues- residents trust their leaders to take the prudent and conservative path that ensures resources remain abundant in the future. That path requires action.
For residents on wells - our recent webinar on well care is a great place to start learning about the aquifer and how to steward your own well for the future.
Please plan to join your neighbors at an important informational meeting on the future of the Poolesville Sole Source Aquifer, the only viable water source for the town.
Poolesville Town Hall
April 21, 7pm
From the Town site:
The Commissioners of Poolesville will be holding an informational hearing to discuss water capacity.
Hydrologists Kathy Mihm and Pat Hammond along with Montgomery County Alliance’s Executor (sic) Director Caroline Taylor will present and discuss recent water capacity studies.
The studies, derived from historical pump data, aquifer models and specific scientific calculations, will be discussed along with solutions for ensuring an adequate water supply for the future.
The informational hearing will be held on April 21, 2025, 7:00pm, at Townhall. It will also be available on YouTube, both live stream and archived for later viewing.
YouTube Channel
Poolesville Town Hall
April 21, 7pm
From the Town site:
The Commissioners of Poolesville will be holding an informational hearing to discuss water capacity.
Hydrologists Kathy Mihm and Pat Hammond along with Montgomery County Alliance’s Executor (sic) Director Caroline Taylor will present and discuss recent water capacity studies.
The studies, derived from historical pump data, aquifer models and specific scientific calculations, will be discussed along with solutions for ensuring an adequate water supply for the future.
The informational hearing will be held on April 21, 2025, 7:00pm, at Townhall. It will also be available on YouTube, both live stream and archived for later viewing.
YouTube Channel
The background - in 2023 MCA funded a study into the future yields of the town's water supply undertaken by seasoned state hydrogeologist Pat Hammond. The results of this study show that current overallocation of water to the town have had an impact on sensitive Horse Penn Branch. Looking ahead, droughts are forecasted to be more frequent and more severe. Seasonal conservation measures will keep the currently sized town population within allocated water limits but new development in the town will necessitate increased conservation measures throughout the year and may cause some wells to dry up.
The study results have informed MCA's Good Gift Groundwater Project seeking to raise awareness about the aquifers under our feet. Recently, the project hosted a webinar all about well care to educate homeowners.
The study results have informed MCA's Good Gift Groundwater Project seeking to raise awareness about the aquifers under our feet. Recently, the project hosted a webinar all about well care to educate homeowners.
