Two cities, one watershed and a lot of flooding
A historical essay based on newspaper accounts, photographs, public records, and watershed studies about flooding in the Lake Merritt and Piedmont areas as El Nino ramps up | Research through October 2026
For more than a century, a hard rain has sometimes turned Grand Avenue into a river. Water has climbed over sidewalks and slipped beneath shop doors, stalled streetcars and automobiles, submerged basements, and forced merchants to reach for sandbags and brooms. At other times it has been Lake Merritt itself that rose, spreading across paths, streets, docks, and parkland. There is even an extraordinary historical photograph of two people rowing a small boat through the flooded Grand Avenue business district.
It is tempting to tell these stories as a series of disasters that happened in Oakland. But that would leave out much of the water—and much of the history. The hills, creeks, streets, and underground pipes of Piedmont are connected to the lower neighborhoods of Oakland and the tidal waters of Lake Merritt. Rain falling in one city may cross the boundary invisibly, moving through a culvert beneath the pavement before reappearing where the land flattens near the lake. The municipal boundary does not stop the watershed. [1]
This has been true through radically different periods of development. In the nineteenth century, Oakland struggled to regulate a tidal inlet and its surrounding lowlands. In the early twentieth, new pavement and rapidly growing neighborhoods put increasing pressure on storm drains. In 1926 and 1927, angry Grand Avenue merchants demanded action while Oakland and Piedmont officials debated where responsibility lay. A much-celebrated drainage project followed in 1936. The devastating storm of October 1962 led to yet another generation of flood-control works. And in the decades after that, the problem of water escaping where it was not wanted became inseparable from another problem: sewage entering streets, creeks, and the lake.
The story is therefore about more than flooding. It is about two cities sharing one landscape, about the changing relationship between a natural estuary and an urban watershed, and about which repairs have improved conditions—and which have not eliminated the underlying risks.
From tidal marsh to paved watershed
1909 Lakeshore Park from Albert E Norman collection I have, colorized by ChatGPT
Before roads and apartment buildings surrounded it, Lake Merritt was a tidal arm of the Oakland Estuary, connected to San Francisco Bay. Creeks flowed down wooded ravines and into its marshes and mudflats. Filling the shoreline, constructing streets and buildings, and placing creeks in pipes changed where water could travel and how quickly it arrived. [1]
Piedmont's creek systems—including Pleasant Valley, Bushy Dell, Wildwood, Indian Gulch/Trestle Glen, and Glen Echo/Cemetery creeks—are part of that story. Water follows the downhill terrain toward the lake even when the stream itself is hidden beneath a street. Oakland's watershed markers, including one near Grand and Lakeshore avenues, make this buried geography visible again. [1]
One distinction is essential throughout this history: storm drains are intended to carry rainfall and runoff, while sanitary sewers carry wastewater from homes and businesses. Both systems may overflow during storms, but a flooded street does not automatically mean it contains sewage. Illegal connections, leaking lines, and excess rainwater entering sanitary pipes created a related—and sometimes overlapping—problem.
Early overflows: 1872–1925
A later Oakland newspaper history described Lake Merritt overflowing in the spring of 1872, inundating several blocks. The retrospective is useful evidence but is not the same as a contemporary flood report. During the following decades, the city repeatedly modified the dam and gates that controlled water between the lake and estuary. [2]
Contemporary newspapers are more specific. In January 1881, a very high tide flooded lowlands and the historic Piedmont Road near Lake Merritt and damaged the Twelfth Street crossing. The reference to “Piedmont Road” does not mean a street in the later incorporated City of Piedmont. In March 1884, rain and high tides again sent water over Twelfth Street and threatened boathouses. In December 1889, reports described an overflowing torrent across the dam, suspended road traffic, and streetcars taking on water. Another overflow followed in January 1890. The recurring difficulty was that rainwater could arrive from the hills precisely when the tide impeded drainage. [2]
The development of the Oakland and Piedmont hills made the problem more complicated. The great February 1907 storm sent water and debris through the Indian Gulch, Pleasant Valley, and Cemetery Creek areas. By 1909, city officials were discussing concrete culverts to reduce flooding at the head of the lake and along Grand Avenue. The January 1916 storms again brought widespread inundation and disruption to Oakland. [3]
Sewage issues were already entangled with drainage decisions. In 1921, Oakland's council approved a proposed joint sanitary sewer improvement requiring a 56 percent Oakland and 44 percent Piedmont cost division; Piedmont's consent was still pending in the report. In 1924, Mayor John L. Davie pressed to stop suspected sewage from entering Lake Merritt, while other officials warned that sealing storm drains could worsen flooding. The argument exposed an enduring tension: moving rainwater away safely without sending contamination into the lake. [4]
1926–1927: Grand Avenue floods—and the cities disagree
The late November 1926 storms provide one of the clearest windows into everyday flooding. Shops and streets near Grand Avenue and Santa Clara Avenue were submerged. An account described Grand Avenue as a small river, with a boat used to ferry stranded people. Key System rail travel was interrupted, storm-sewer covers were forced upward, and merchants reported damaged merchandise and basements. City crews worked to clear drains as residents demanded immediate action. [5]
The public argument quickly became political. Business owners complained that poor street grading and inadequate sewers had made recurring flooding almost predictable. Some were angry about being charged for paving that, they believed, had worsened the problem. Officials debated lake gates, stormwater capacity, emergency maintenance, and who would pay for a lasting remedy. [5]
An Oakland Tribune report dated February 3, 1927, citing engineering work, identified a 781-acre Grand Avenue drainage basin, with 549 acres in Piedmont—roughly 70 percent of that particular basin. Engineers described alternative six-foot pressure-sewer routes priced at $137,300 and $156,400. These were proposals, not evidence that the projects were built at those prices. Nor did the watershed acreage alone settle legal responsibility. [6]
Oakland officials sought regional financial help, while Piedmont rejected the suggestion it was simply responsible for Grand Avenue's floods. One report said Piedmont had already contributed $65,000 in 1925 toward joint sewer work. The newspaper record presents opposing views from both governments. What it demonstrates beyond dispute is that water crossing the city line made flood protection a shared engineering problem, even when agreement over cost-sharing proved elusive. [6]
The big promise of 1936—and the floods that followed
As the 1920s ended, Oakland studied additional drainage works and altered its floodgates. Newspaper reports from 1932–1933 describe new electrically operated gates replacing slower wooden mechanisms. On several occasions officials or editorial writers celebrated seasons in which Grand Avenue had remained dry. But flood complaints and calls for a larger storm sewer returned. [7]
The major investment came in 1936. On October 16, the Oakland Tribune and Oakland Post-Enquirer celebrated completion of the $355,000 Grand Avenue drainage project. The reporting described about 4,100 feet of six-foot concrete pipe running from the Piedmont line near Wildwood toward the Embarcadero, and eight months of construction with substantial daily employment. The Grand Avenue Merchants Association marked completion with public festivities and a newspaper advertisement thanking those responsible. [8]
The improvement addressed a serious capacity problem and represented a substantial public investment. But it did not end all later flooding in the watershed. In 1947, an Oakland Tribune feature on the city's “forgotten creeks” noted how enclosing waterways created continuing drainage difficulties. Heavy storms again flooded Oakland in January 1950, and on December 28, 1951, lake water covered the docks and boathouse area and submerged part of a lakeside walkway. These events do not necessarily show failure of the particular 1936 pipe: shoreline overflow, blocked neighborhood drains, and inadequate sewer capacity can occur at different locations. [9]
October 1962: A decisive flood-control turning point
The October 12–13, 1962 storm became the defining modern event in Lake Merritt's flood history. Runoff overwhelmed the lake area and flooded nearby streets, including Grand Avenue. The historic film linked at the beginning of this article preserves some of that upheaval. Because the compilation also includes other East Bay locations, individual scenes require careful identification. [10]
Later accounts disagree on the exact 24-hour rainfall figure: one reports 4.47 inches, another 9.4 inches. The difference may reflect measurement locations or intervals and should not be silently reconciled. They agree that the flood was severe and that the lake rose unusually high. The city's 2004 Safety Element identified the 1962 event as a major turning point in local flood-control planning. [10]
Alameda County established Flood Control Zone 12, covering Oakland and Emeryville. Piedmont declined to join, drawing criticism from county officials who stressed the upper watershed's contribution to downstream runoff. This revived the same basic disagreement visible in the 1920s: who benefits from protection, and who should finance it? [11]
Engineers then proposed much stronger lake-outlet controls. Initial 1964 pumping-station designs were controversial because a large facility at the edge of the lake threatened open space, views, and plans for nearby civic institutions. Other schemes envisioned moving the plant, altering the tidal channel, or even creating another small lake near the future Laney College campus. [11]
A more integrated scheme eventually advanced with county and federal support. Groundbreaking was reported in April 1969, with construction and operation completed around 1970–1971; sources use different dates for those milestones. The Seventh Street pumping station uses gates, gravity discharge, and large pumps to control lake levels when conditions are unfavorable for natural outflow. It greatly increased protection against lake overflow, but it cannot prevent every clogged drain or every extreme event throughout the watershed. [12]
Sewage, pollution, and Piedmont: a related history
Floodwater could also reveal failures in a different system: sanitary sewers. In 1949, allegations linked Piedmont drainage to deaths of fish and birds in Lake Merritt. Oakland health and engineering officials disputed claims that sewage was directly discharged from Piedmont, while acknowledging that storm sewers could sometimes carry contaminated water. The article records conflicting assertions—not a definitive explanation of the wildlife losses. [13]
The issue resurfaced forcefully in August 1975. County health officials found high bacterial readings and restricted water-contact recreation. Reports traced an apparently improper sewer connection to the vicinity of 107 Wildwood Avenue and Wildwood Avenue at Sylvan Way in Piedmont, where sewage was said to have reached an Oakland storm drain that discharged to the lake. Piedmont officials reported repairs and disputed the implication that the city was responsible for all contamination; other investigators believed multiple sources remained possible. [13]
In January 1977, sewage reportedly overflowed onto streets in both cities during heavy rain. County water samples from Lake Merritt exceeded contemporary health standards. Later that year, newspaper coverage described algae and widgeon grass, fueled in part by nutrients in incoming runoff. Flood control had another environmental complication: restricting tidal exchange helped manage lake levels but could worsen stagnant-water conditions. The long-term problem required both hydraulic capacity and cleaner water. [14]
Piedmont's later improvements reflect this distinction. In 2001, it obtained a $16 million state-backed credit line toward rehabilitating roughly twenty miles of deteriorating sanitary sewers. Cracked pipes and groundwater infiltration can overload wastewater systems during storms; repairing them reduces that risk but does not replace the storm drains needed for rainwater. [15]
After the pumps: 1998 to the present
The pumping station helped keep the lake under control during many storms, but the 1997–1998 El Niño period proved that Grand Avenue businesses were still vulnerable. Newspapers described sandbags and barriers, flooded shops, blocked traffic, and emergency city response. The distinction between a lake whose outlet is managed and a neighborhood whose smaller pipes overflow remained painfully visible. [15]
Further flooding led to a $6.4 million Lakeshore Avenue drainage improvement planned in the early 2000s, with larger underground pipes installed in stages toward Prince Street. December 2003 photographs again show water in the Grand Avenue area. More recently, a December 2014 photograph recorded flooding on Lakeshore Avenue, and in January 2019 workers cleared storm drains as water covered part of a Grand Avenue sidewalk. [15][16]
Not every high-water episode is the same kind of flood. October 2020 tides pushed water onto lakeside walks; the December 2022 atmospheric river inundated parts of the shoreline; and unusual lake levels affected paths in September 2026. These should not automatically be described as Grand Avenue street floods. [16]
Piedmont itself was seriously affected by the storms around New Year's 2023: the city declared a local emergency after flooding, landslides, fallen trees, and other damage. In 2025, it completed several local storm-drain upgrades and installed a bioswale at Grand and Fairview, designed to slow and filter some runoff. These hillside projects and Oakland's lower-elevation defenses address different parts of a connected system. [17]
Oakland faces a wider infrastructure challenge. In October 2026, reporting on its storm-drain master planning described 30–40 percent of the city's system as needing rehabilitation or replacement, with a $3.6 billion long-term need. These are estimated requirements, not completed repairs or funds already secured. [18]
What has worked, and what hasn't?
Tide gates and pumping: They have substantially improved control over lake levels. Operating gates to release water by gravity, and pumping when gravity is inadequate, are real advances. Their limitation is physical: capacity is finite, tides can be extreme, and low-lying streets also rely on their own drains. [12]
Larger storm sewers: The 1936 Grand Avenue pipe and later Lakeshore upgrades addressed known bottlenecks. They helped the places served by those systems, but they do not prove that every future storm, inlet, basement, and intersection is protected. Cleaning an obstructed drain also restores flow; it cannot make an undersized pipe larger. [8][15]
Sanitary-sewer repairs and water-quality work: Separating wastewater from rainwater, inspecting improper connections, and rehabilitating aging pipes reduce sewage spills. These measures respond to a different risk than a lake overflowing its shoreline. More tidal exchange may improve water quality, but requires coordinated control when high water threatens. [13][14]
Maintenance, open creeks, and green infrastructure: Keeping debris out of drains, maintaining creek channels, and adding features such as bioswales can slow and filter runoff. They complement major pipes and pumps rather than replacing them. Neither city can manage a shared watershed well by considering only the water inside its own limits. [1][17]
Two cities, one continuing responsibility
For more than a century, the Grand Lake neighborhood has exposed the limits of treating rainwater as a problem that ends at a city boundary. Oakland and Piedmont have disagreed about drainage costs and sources of pollution, but their pipes, creeks, and downstream lake remain connected. The historical record does not show that Piedmont caused every Grand Avenue flood, nor that any one project was a total failure simply because flooding recurred elsewhere.
It shows something more useful: improvements can work while leaving other vulnerabilities unsolved. The nineteenth-century gates answered one problem; the 1936 pipe answered another; the pumps after 1962 changed the lake's flood protection; sanitary-sewer rehabilitation addressed contamination; and current maintenance and stormwater projects meet newer demands. Taken together, those efforts tell a history of two cities learning—sometimes cooperatively, sometimes reluctantly—to live with one watershed.
Source notes
[1] Alameda County Flood Control District, ‘Indian Gulch and Pleasant Valley Creeks Watershed’; City of Piedmont, Clean Water Program; City of Oakland, ‘Watershed Markers: Creeks Beneath Your Feet’; Piedmont General Plan (watershed and drainage).
[2] Oakland Tribune historical retrospectives on the spring 1872 flood; Oakland Tribune, June 1, 1878 and Jan. 29, 1881; Daily Evening Vidette, Mar. 27, 1884; Oakland Tribune / The Morning Times, Dec. 1889–Jan. 1890.
[3] Oakland Enquirer, Feb. 2, 1907; Oakland Tribune, Apr. 23, 1909 and Jan. 3, 1916; San Francisco Chronicle, Jan. 4, 1916.
[4] Oakland Tribune, Oct. 6, 1921 (joint sewer proposal), and Apr. 10, 1924 (storm-sewer closure and lake pollution debate).
[5] Oakland Tribune, Nov. 20, 26–27, 1926; Oakland Post-Enquirer, Nov. 26–27, 1926 (flood reports, photographs, transit interruption, and merchants' petitions).
[6] Oakland Tribune, Feb. 3 and 18, 1927; San Francisco Chronicle, Feb. 5, 1927 (basin area, proposed sewer routes, and competing city positions).
[7] Oakland Post-Enquirer, Apr. 23, 1929 (map of proposed sewers); Oakland Tribune, Nov.–Dec. 1932 and Jan. 1933 (new electrical floodgates).
[8] Oakland Post-Enquirer, Jan. 10, 1935 and Oct. 16, 1936, p. 19; Oakland Tribune, Oct. 16, 1936, p. 24 (completion, dimensions and public celebration).
[9] Dave Hope, ‘Oakland's Forgotten Creeks,’ Oakland Tribune, Feb. 1, 1947; Oakland Post-Enquirer, Jan. 17, 1950; Oakland Tribune, Dec. 28, 1951, p. 17.
[10] City of Oakland, General Plan Safety Element (2004), Flooding Hazards; Oakland LocalWiki, ‘Storms of 1962’ and linked film; East Bay Times, Dec. 28, 2012; Lake Merritt Institute (differing rainfall figures).
[11] Oakland Tribune, Nov. 29, 1962 and Jan. 2, 1963 (Zone 12 and Piedmont); Oakland Tribune, Aug.–Sept. 1964 and Jan.–Feb. 1966 (pumping-station plans and alternatives).
[12] San Francisco Examiner / Chronicle, Dec. 1968; Oakland Tribune, Apr. 27, 1969; East Bay Times, Dec. 28, 2012 (construction, completion, and station operations).
[13] Oakland Tribune, July 6, 1949 (‘Lake Sewage Charge Denied’), and Aug. 7–29, 1975 (health warnings, 107 Wildwood Avenue, Sylvan Way and responses from Piedmont officials).
[14] Oakland Tribune, Feb. 16 and June 1, 1977 (sewer overflows, bacteria, algae); Lake Merritt Institute, ‘White Paper on Water Level Control and Tidal Flows’ (2002 update).
[15] Oakland Tribune, Jan.–Apr. 1998 (El Niño and merchants); Mar. 20, 2001 (Piedmont sewer rehabilitation); 2003 articles on Lakeshore drainage works and Grand Avenue flooding.
[16] San Francisco Chronicle, Dec. 2014 and Jan. 2019 flood photographs; Lake Merritt Institute, Oct. 2020 newsletter; 2022 atmospheric-river reporting; ABC7, Sept. 5, 2026 (lake-path flooding).
[17] Piedmont Exedra, Jan. 2023 emergency report and Oct. 2026 storm-preparedness report; City of Piedmont, Clean Water Program and Grand/Fairview bioswale announcement (2025).
[18] City of Oakland, Storm Drainage Master Plan; Chase Hunter and Veronica Martinez, ‘Oakland's aging storm drains need $3.6 billion in repairs,’ Bay Area News Group, Oct. 8, 2026. Figures are estimates, not appropriations.
Selected online records: Piedmont Clean Water · Oakland buried-creek markers · Piedmont 2023 emergency · Oakland 2026 infrastructure report
Image and publication notes
All historical newspaper images reproduced in this working document were supplied for the research project. The 1962 film is linked to its original YouTube page rather than copied. Period descriptions of the “Piedmont road,” proposed projects, and contested sewage claims have been retained with appropriate qualifications.
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