This article originally appeared in the latest issue of History News<\/a>, AASLH\u2019s member magazine. Members can access a digital copy of the issue for free in our Resource Center<\/a>.<\/em><\/p>\n Let\u2019s\u00a0be honest with ourselves: historic\u00a0preservation has gotten harder over the last few decades.\u00a0So many new and shifting challenges need to be addressed when\u00a0protecting,\u00a0the history of this nation\u00a0for generations to come.\u00a0Changes in building materials, attacks from unknown pests, paint recipes that change monthly\u00a0and,\u00a0a growing danger, water.\u00a0We could debate for some time the reasons why, but that is not the point of this article.\u00a0Winning the war on these\u00a0threats to historic preservation\u00a0is the goal\u00a0and a major concern at my own site.<\/span>\u00a0<\/span><\/p>\n Strawbery\u00a0Banke Museum<\/a> is an outdoor living history site in Portsmouth, New Hampshire, consisting of nine acres and thirty-two historic buildings on their original foundations built between the seventeenth and nineteenth century. This campus is blessed with a geographic location in downtown Portsmouth that is both picturesque and a growing destination for tourists. Unfortunately, the campus is also prone to flooding from both surface water and groundwater. Tidal impacts from the nearby Piscataqua River influence groundwater levels (called upwelling) until they impact our building basements. Water-impacted basements, in turn, cause extremely high relative humidity levels for extended periods of time. This leads to more rapid decay of most building materials and damage to vital utilities. In addition, large rain events deposit stormwater on the campus, a low point in the South End neighborhood, which ponds around our buildings and blocks visitor access. The frequency of these events is increasing and recently hit a new high when a storm in January 2024 saw the highest ever recorded tides in the Piscataqua River combined with many inches of rainfall\u2014the perfect storm for multiple building and site-wide impacts.<\/span>\u00a0<\/span><\/p>\n The center of the\u00a0Strawbery\u00a0Banke campus is a large field that was once a tidal inlet called Puddle Dock, a safe harbor that played a significant role in the development of this historic site and the city.\u00a0The waterway was filled in by the\u00a0city of Portsmouth in 1902-1903.\u00a0This one action further complicates our flooding impacts since our\u00a0\u201cconnection\u201d\u00a0to the river, where all our stormwater ends up, was cut off except for\u00a0a single\u00a030-inch pipe\u00a0when Puddle Dock was filled\u00a0in.<\/span>\u00a0<\/span><\/p>\n The question now becomes: how do we manage all this water at our site until the one pipe can send it on its way? Like most of the field, our museum staff consists of historians, fundraisers, and educators, not plumbers or water engineers. We have no backgrounds or skill sets that make us competent to answer this crucial question. So we get help, form partnerships, and build a team. Out in our communities are a growing number of experts like landscape architects, civil engineers, hydrologists, and environmental services to help us solve this challenge. Once we have defined the impacts, we can better define the people whose help we need to be successful.<\/span>\u00a0<\/span><\/p>\n More and more landscape architects are specializing in this kind of work. Strawbery Banke Museum hired one along with an architect to develop a site-wide stormwater plan in June 2023 to identify the causes of surface flooding, the impact areas, and the general \u201ctools\u201d we can use to mitigate these problems. Some of these tools sound like\u00a0\u00a0common sense. Did you ever play at the beach controlling the incoming waves or tide by building moats, canals, and walls? Same idea. With smart design, we can reduce (less water, less impact), capture (dam it up), store (hold it in a specific area), and control (move it along in safe areas) the water away from the areas that will cause damage. One, or likely more than one, of these tools will work to solve flooding impacts. As an example, the flood-prone area in our management plan known as \u201cArea of Concern 2\u201d is caused by city stormwater entering our site from Washington Street combined with runoff from the higher, northern boundary of Strawbery Banke. The solution involved the use of several of these \u201ctools\u201d through the creation of a number of landscape changes. Specifically, two rain gardens or bio-retention ponds, three drainage swales, and one sidewalk \u201cdam.\u201d This coupled with a regrading of the museum\u2019s roads in this area will completely redefine how the flood waters flow through this area, keeping it away from the historic houses and into the created management areas.<\/span>\u00a0<\/span><\/p>\n In all, the museum\u2019s campus has nine areas that will need this type of stormwater treatment. We are working on all of them to some degree, but in different phases from planning to design to implementation. As we look deeper into each impacted area, we keep in mind our main mission to teach the history of our museum\u2019s neighborhood. Are there crossover areas where stormwater management and site history interconnect? We are finding the answer is a resounding \u201cyes!\u201d <\/span>As the museum and the design team plan future work, we look to create a bio-retention pond that evokes the look of the old tidal inlet with wharves and native plants. We then strategically place site signage with historic images of the old inlet before it was filled in. Planning also involves the retoration of an important archaeological site which today is nothing more than sections of an old foundation in the grass. We\u2019ll then use this foundation for storing stormwater and to tell the story of the Marshall Pottery site, which produced vital redware vessels for the local community and had three enslaved individuals\u00a0laboring there.\u00a0<\/span><\/p>\n Unfortunately, surface water treatments or mitigation strategies only get Strawbery Banke part of the way to resiliency. You may recall the site is also plagued by groundwater impacts or groundwater intrusion. This has to be handled in a slightly different way and with a slightly different team of partners. One partner in finding groundwater solutions is the University of New Hampshire Geospatial Science Center.They installed and maintain for Strawbery Banke a groundwater sensor network studying how groundwater is moving on our site. This information is vital to finding the right strategy to protect our historic resources.<\/span>\u00a0<\/span><\/p>\n An important structure benefiting from this strategy is the Penhallow-Cousins House. The 1750 building was moved to the site in 1862 when it was an active, growing residential neighborhood, long before the museum was created. The chosen site was reclaimed land, part of the Puddle Dock tidal inlet, that was the out-flow to another body of water known as the South Mill Pond. In fact, archaeological investigation of this area prior to the foundation work on the house uncovered a cobble spillway feature, indicating attempts at early water management from the late eighteenth century. In 1862, the house was placed on a loose stone foundation with a dirt floor. As groundwater levels increased over the decades, the basement was plagued by high humidity levels and later impacted by standing water as well. The result was rapid decay of both brick and wood structural elements of the house. Looking at our treatment options, we chose a new wet-proof foundation that allows groundwater to drain in and out freely. The entire foundation, inside and out, has perforated pipes connected to the city storm water system to manage this groundwater. Flood vents on the rear elevation of the new foundation and a sump pump add protection from water impacting the undercarriage of the house. <\/span>\u00a0<\/span><\/p>\n Each location and example of water impact must be studied and understood to determine the best course of action. Fortunately all the treatments available to us are now part of the National Park Service Guidelines on Flood Adaptation<\/a>. The guidelines are flexible by design since each case will bring unique qualities needing unique solutions. Each successful adaptation will land somewhere on the line between historic preservation and resiliency. It is finding the balance that takes time and plenty of support. <\/span>\u00a0<\/span><\/p>\n![\"\"](\"https:\/\/aaslh.org\/wp-content\/uploads\/2025\/12\/HN-79.3-1024x576.png\")
<\/a>By Rodney Rowland, Director of Environmental Sustainability, <\/span><\/i>Strawbery Banke Museum<\/em><\/p>\n![\"\"](\"https:\/\/aaslh.org\/wp-content\/uploads\/2025\/12\/SBAerial20150807-06-1024x768.jpg\")
<\/a><\/p>\n![\"\"](\"https:\/\/aaslh.org\/wp-content\/uploads\/2025\/12\/SB-houses-1024x680.jpg\")
<\/a><\/p>\nWe are storing stormwater\u00a0and\u00a0teaching history\u00a0at the same time.<\/span>\u00a0<\/span><\/h3>\n
![\"\"](\"https:\/\/aaslh.org\/wp-content\/uploads\/2025\/12\/foundation-work-1024x768.jpg\")
<\/a><\/p>\nThe decision to remove this historic foundation was not an easy one, but we must find the balance between historic preservation and resiliency. <\/span><\/h3>\n
![\"\"](\"https:\/\/aaslh.org\/wp-content\/uploads\/2025\/12\/garden-club-300x225.jpg\")
<\/a>The moral of this story is solutions are there to battle these new and growing threats, but success is dependent on seeking the partnerships one needs to formulate a plan. In this example, it really does take a village. Strawbery Banke is blessed with help from paid consultants, volunteers, state and city employees, and the greater community as a whole. We also seek advice from a regional group called the New Hampshire Coastal Adaptation Workgroup. This is a volunteer-run organization whose mission includes helping with the regional response to flooding. Its members represent numerous disciplines offering an incredible opportunity for those needing guidance. More and more of these types of regional groups are popping up, so find out if your community has one. A favorite partnership came from the local Piscataqua Garden Club. They awarded us a grant for the native plants that would go in our new rain gardens and then came on-site to plant them. It takes a village!<\/span>