Landslide Monitoring and Research in the Atlantic Highlands area, New Jersey Active
Recent shallow landslides have occurred on the steep hillslopes of the Atlantic Highlands area during and after large storm events with exceptionally heavy rainfall. These shallow landslides have resulted in extensive damage to residential property and local infrastructure and threatened human safety.The USGS New Jersey Water Science Center (NJWSC) and the USGS Landslide Hazards Program (LHP) are currently monitoring hillslopes within the Atlantic Highlands area of NJ to better understand the hydrologic and meteorological conditions associated with shallow landslide initiation.
Introduction
Landslides on the steep coastal bluffs of the Atlantic Highlands area (Boroughs of the Atlantic Highlands and Highlands) in Monmouth County, NJ have been recurring, punctuated events through recorded and pre-recorded history. Both shallow and deep-seated landslides have occurred in this area episodically, with the oldest, documented deep-seated landslide occurring in April of 1782 (Minard, 1974). However, the recent landslides have been mostly shallow in nature and have occurred during large storm events with exceptionally heavy rainfall. Landslides of these types can be triggered on unstable slopes by intense and/or sustained rainfall and rapid changes in pore-water pressure.
The recent shallow landslides in the area consist primarily of slumps and flows of earth and debris within areas of historic landslides or on slopes modified by human activities (Ashland and others, 2017). Such landslides are typically triggered by increases in shallow soil moisture and pore-water pressure caused by sustained and intense rainfall associated with spring nor’easters and late summer-fall tropical cyclones. However, the critical relationship between rainfall, soil moisture conditions, and land movement has not been fully defined.
Objective
The objective of the USGS landslide research within the Atlantic Highlands area is to continuously monitor hydrological and meteorological conditions to identify conditions that destabilize a hillslope. The hydrologic monitoring data provide insights into the role of antecedent soil moisture on hydrologic storm response and seasonal variations in slope stability in the coastal bluffs.
Scientists at the USGS will use the monitoring results to:
-
Evaluate changes in soil moisture and pore-water pressure caused by storms of varying duration, intensity, cumulative rainfall amounts, and seasonality;
-
Identify how seasonal variations in soil moisture and pore-water pressure affect landslide susceptibility; and
-
Quantify the critical rainfall conditions that correspond to shallow landslide occurrence.
Current Landslide Monitoring Sites
USGS monitoring efforts began in August 2015 at two historic landslide locations, below the Ocean Boulevard Bridge (OBB) and below Mount Mitchell Scenic Overlook (MMSO). Continuous monitoring data is collected for the following parameters:
- Rainfall (MMSO only),
- Soil moisture,
- Groundwater conditions (pore-water pressure), and
- Downslope movement.
Near real-time data are collected continuously and recorded every 15 to 60 minutes on a datalogger. Site visits are routinely made to download data, perform maintenance, and conduct visual inspections.
Current Monitoring: Relevance and Benefits
Continuation of the landslide monitoring network is highly relevant to the citizens and community along the north flank of the Atlantic Highlands area. Long-term data from the continuous monitoring will help to refine provisional seasonal rainfall thresholds recently developed for landslides in the Atlantic Highlands area (Ashland et al, 2017). The data can also be used by community members or municipality officials to mitigate landslide hazards. In the future, the data collected on hydrologic response and movement during major storms could be incorporated into a near-real time prototype landslide warning network. Near real-time monitoring systems could be crucial in identifying active or imminent landslide hazards.
On a regional level, this approach may have broad applications to other unstable hillslopes in New Jersey and the northeast. This joint effort by two USGS Mission Area Programs (Hazards and Water) is consistent with USGS goals of advancing knowledge of the regions natural systems, investigating interdisciplinary processes and providing scientific technical support and information to local and federal agencies.
Acknowledgements
The study was funded by the Disaster Relief Appropriations Act of 2013 (PL 113–2) and the USGS Landslide Hazards Program. The USGS would like to thank the Monmouth County Parks System and the Borough of the Atlantic Highlands for their ongoing cooperation and collaboration on the project.
Hydrologic, slope movement, and soil property data from the coastal bluffs of the Atlantic Highlands, New Jersey, 2016-2018
Conditions associated with shallow landslides in the Atlantic Highland
Capturing the transient hydrological response in sandy soils during a rare cloudburst associated with shallow slope failures; A case study in the Atlantic Highlands, New Jersey, USA
Landslide monitoring in the Atlantic Highlands area, New Jersey
Characterizing meteorological and hydrologic conditions associated with shallow landslide initiation in the coastal bluffs of the Atlantic Highlands, New Jersey
Slump blocks in the Atlantic Highlands of New Jersey
- Overview
Recent shallow landslides have occurred on the steep hillslopes of the Atlantic Highlands area during and after large storm events with exceptionally heavy rainfall. These shallow landslides have resulted in extensive damage to residential property and local infrastructure and threatened human safety.The USGS New Jersey Water Science Center (NJWSC) and the USGS Landslide Hazards Program (LHP) are currently monitoring hillslopes within the Atlantic Highlands area of NJ to better understand the hydrologic and meteorological conditions associated with shallow landslide initiation.
Introduction
Landslides on the steep coastal bluffs of the Atlantic Highlands area (Boroughs of the Atlantic Highlands and Highlands) in Monmouth County, NJ have been recurring, punctuated events through recorded and pre-recorded history. Both shallow and deep-seated landslides have occurred in this area episodically, with the oldest, documented deep-seated landslide occurring in April of 1782 (Minard, 1974). However, the recent landslides have been mostly shallow in nature and have occurred during large storm events with exceptionally heavy rainfall. Landslides of these types can be triggered on unstable slopes by intense and/or sustained rainfall and rapid changes in pore-water pressure.
The recent shallow landslides in the area consist primarily of slumps and flows of earth and debris within areas of historic landslides or on slopes modified by human activities (Ashland and others, 2017). Such landslides are typically triggered by increases in shallow soil moisture and pore-water pressure caused by sustained and intense rainfall associated with spring nor’easters and late summer-fall tropical cyclones. However, the critical relationship between rainfall, soil moisture conditions, and land movement has not been fully defined.
Objective
The objective of the USGS landslide research within the Atlantic Highlands area is to continuously monitor hydrological and meteorological conditions to identify conditions that destabilize a hillslope. The hydrologic monitoring data provide insights into the role of antecedent soil moisture on hydrologic storm response and seasonal variations in slope stability in the coastal bluffs.
Scientists at the USGS will use the monitoring results to:
-
Evaluate changes in soil moisture and pore-water pressure caused by storms of varying duration, intensity, cumulative rainfall amounts, and seasonality;
-
Identify how seasonal variations in soil moisture and pore-water pressure affect landslide susceptibility; and
-
Quantify the critical rainfall conditions that correspond to shallow landslide occurrence.
Current Landslide Monitoring Sites
USGS monitoring efforts began in August 2015 at two historic landslide locations, below the Ocean Boulevard Bridge (OBB) and below Mount Mitchell Scenic Overlook (MMSO). Continuous monitoring data is collected for the following parameters:
- Rainfall (MMSO only),
- Soil moisture,
- Groundwater conditions (pore-water pressure), and
- Downslope movement.
Near real-time data are collected continuously and recorded every 15 to 60 minutes on a datalogger. Site visits are routinely made to download data, perform maintenance, and conduct visual inspections.
Current Monitoring: Relevance and Benefits
Continuation of the landslide monitoring network is highly relevant to the citizens and community along the north flank of the Atlantic Highlands area. Long-term data from the continuous monitoring will help to refine provisional seasonal rainfall thresholds recently developed for landslides in the Atlantic Highlands area (Ashland et al, 2017). The data can also be used by community members or municipality officials to mitigate landslide hazards. In the future, the data collected on hydrologic response and movement during major storms could be incorporated into a near-real time prototype landslide warning network. Near real-time monitoring systems could be crucial in identifying active or imminent landslide hazards.
On a regional level, this approach may have broad applications to other unstable hillslopes in New Jersey and the northeast. This joint effort by two USGS Mission Area Programs (Hazards and Water) is consistent with USGS goals of advancing knowledge of the regions natural systems, investigating interdisciplinary processes and providing scientific technical support and information to local and federal agencies.
Acknowledgements
The study was funded by the Disaster Relief Appropriations Act of 2013 (PL 113–2) and the USGS Landslide Hazards Program. The USGS would like to thank the Monmouth County Parks System and the Borough of the Atlantic Highlands for their ongoing cooperation and collaboration on the project.
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- Data
Hydrologic, slope movement, and soil property data from the coastal bluffs of the Atlantic Highlands, New Jersey, 2016-2018
Seasonal variations in vegetation, rainfall, and soil moisture conditions have the potential to impact the slope stability of locally forested coastal bluffs in the Atlantic Highlands of New Jersey. Both the seasonality and rainfall amounts of the two types of storms that induce shallow landslides in the area vary considerably. Most of the documented historical landslides are the result of heavy r - Publications
Conditions associated with shallow landslides in the Atlantic Highland
Capturing the transient hydrological response in sandy soils during a rare cloudburst associated with shallow slope failures; A case study in the Atlantic Highlands, New Jersey, USA
A cloudburst on 7 August 2018 in the coastal bluffs of the Atlantic Highlands, New Jersey, induced flooding, erosion and multiple shallow slope failures that adversely affected the surrounding hillside residential area. Historically, short-duration deluges are rare in the New York Bay region, with only eight cloudbursts of greater magnitude documented since 1948. The coastal bluffs consist of a vaAuthorsFrancis Ashland, Pamela A. Reilly, Alex R. FioreLandslide monitoring in the Atlantic Highlands area, New Jersey
Shallow and deep-seated landslides have occurred episodically on the steep coastal bluffs of the Atlantic Highlands area (Boroughs of Atlantic Highlands and Highlands) in New Jersey. The oldest documented deep-seated landslide occurred in April 1782 and significantly changed the morphology of the bluff. However, recent landslides have been mostly shallow in nature and have occurred during large stAuthorsPamela A. Reilly, Francis X. Ashland, Alex R. FioreCharacterizing meteorological and hydrologic conditions associated with shallow landslide initiation in the coastal bluffs of the Atlantic Highlands, New Jersey
Meteorological and hydrologic conditions associated with shallow landslide initiation in the coastal bluffs of the Atlantic Highlands, New Jersey remain undocumented despite a history of damaging slope movement extending back to at least 1903. This study applies an empirical approach to quantify the rainfall conditions leading to shallow landsliding based on analysis of overlapping historical precAuthorsFrancis Ashland, Alex R. Fiore, Pamela A. ReillySlump blocks in the Atlantic Highlands of New Jersey
No abstract available.AuthorsJames Pierson Minard