This resource contains Lidar-DEM collection status shapefiles from the Texas Natural Resources Information System (TNRIS) [http://tnris.org]. November 2023 updates: this year, TNRIS changed its name to Texas Geographic Information Office (TxGIO). The domain name hasn't changed yet, but the data hub is continually evolving. See [1], [2] for current downloadable data.

For purposes of Hurricane Harvey studies, the 1-m DEM for Harris County (2008) has also been uploaded here as a set of 4 zipfiles containing the DEM in tiff files. See [1] for a link to the current elevation status map and downloadable DEMs.
Project name: H-GAC 2008 1m Datasets: 1m Point Cloud, 1M Hydro-Enforced DEM, 3D Breaklines, 1ft and 5ft Contours Points per sq meter: 1 Total area: 3678.56 sq miles Source: Houston-Galveston Area Council (H-GAC) Acquired by: Merrick, QA/QC: Merrick Catalog: houston-galveston-area-council-h-gac-2008-lidar

References: [1] TNRIS/TxGIO StratMap elevation data [https://tnris.org/stratmap/elevation-lidar/] [2] TNRIS/TxGIO DataHub [https://data.tnris.org/]

LiDAR grid coverage for the 2018 product (HCFCD Extent).

This digital elevation model (DEM) is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Coastal Services Center's Sea Level Rise and Coastal Flooding Impacts Viewer. The DEM includes the 'best available' lidar data known to exist at the time of DEM creation that meets project specifications for those counties within the boundary of the Houston/Galveston TX Weather Forecast Office (WFO), as defined by the NOAA National Weather Service. The counties within this boundary are: Jackson, Matagorda, Brazoria (portion), Harris (portion), Galveston, and Chambers. For all the counties listed, except for Harris, the DEM is derived from LiDAR data sets collected for the Texas Water Development Board (TWDB) in 2006 with a point density of 1.4 m GSD. LiDAR data for Harris County was collected in October 2001 by the Harris County Flood Control District Tropical Storm Allison Recovery Project (TSARP) with a point density of 2.0 m GSD. Hydrographic breaklines used in the creation of the DEM were delineated using LiDAR intensity imagery generated from the data sets. The DEM is hydro flattened such that water elevations are less than or equal to 0 meters.The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 10 meters.

The NOAA Coastal Change Analysis Program (C-CAP) produces national standardized land cover and change products for the coastal regions of the U.S. C-CAP products inventory coastal intertidal areas, wetlands, and adjacent uplands with the goal of monitoring changes in these habitats through time. The timeframe for this metadata is summer 2020. These maps are developed utilizing high resolution aerial imagery, along with lidar and various available ancillary information, and can be used to track changes in the landscape through time. This trend information gives important feedback to managers on the success or failure of management policies and programs and aid in developing a scientific understanding of the Earth system and its response to natural and human-induced changes. This understanding allows for the prediction of impacts due to these changes and the assessment of their cumulative effects, helping coastal resource managers make more informed regional decisions.

LiDAR grid coverage for the 2014 product.

This dataset provides four digital elevation models derived from airborne lidar data acquired over four separate areas along and adjacent to the Fairweather Fault along the remote Gulf of Alaska coast within Glacier Bay National Park. In 1958, the Fairweather Fault in southeast Alaska ruptured over 260 km between Yakutat Bay and Cross Sound, producing the magnitude 7.8 Lituya Bay earthquake. To better understand the extent of surface rupture and identify sites to investigate for evidence of past earthquakes, the USGS Alaska Science Center collaborated with the National Park Service, the Army Corps of Engineers' Cold Regions Research and Engineering Laboratory (CRREL), and the National Center for Airborne Lidar Mapping (NCALM) at the University of Houston to collect over 166 square kilometers of high-resolution airborne lidar (Light Detection and Ranging) data. CRREL developed and deployed the Helipod lidar system, designed for use on a Robinson R44 Raven II helicopter, to acquire more than 34.4 million laser measurements. The measurements have vertical and horizontal accuracies of +/-10 cm. NCALM processed the lidar data to remove laser returns from vegetation and enhance laser returns from the ground surface. The derivative “bare-Earth” data include 1.4 to 2.3 laser returns per square meter, which were used to produce 1-m-per-pixel digital elevation models (DEM) for four areas between Lituya Bay and Icy Point.

This resource describes a dataset of gridded depth at horizontal resolution of 3 meters, published November 15, 2017, downloaded from FEMA [1] and hosted in this archive at the University of Texas Advanced Computing Center (TACC) [2].. The raster dataset is contained within an Esri ArcGIS geodatabase. This product utilized Triangulated Irregular Network (TIN) interpolation, four quality assurance measures (identifying dips, spikes, duplication, and inaccurate/unrealistic measurements). High Water Marks were obtained from the Harris County Flood Control District (HCFCD), US Geological Survey (USGS), and other inspection data. Elevation data comprised a mosaic of 3 meter resampled elevations from 1M & 3M LiDAR, and IFSAR data. One section of the IfSAR data was found to be erroneous, and replaced with a blended 10 meter section. [This description was in correspondence January 22, 2018, from Mark English, GeoSpatial Risk Analyst, FEMA Region VIII, Mitigation Division.]

A preliminary version of these depths dated September 10, 2017 can be viewed in a FEMA web map [3]. This web map shows a forecasted depth grid, based on National Weather Service (NWS) Advanced Hydrologic Prediction Service (AHPS) forecasted water levels.

See FEMA's Natural Hazard Risk Assessment Program (NHRAP) ftp site [4] for additional HWM-based depth grids and inundation polygons: - Harris County AOIs and Inundation Boundaries [5] - Harris County Depth Grids [6] - Aransas, Nueces, and San Patricio Coastal Depth Grids and Boundaries [7] FEMA notes on these Modeled Preliminary Observations: o Based on observed Water Levels at stream gauges interpolated along rivers, downsampled to 5m resolution DEM o Depth grids updated with new observed peak crest as they become available o Will include High Water Mark information as it becomes available o Extents validated with remote sensing o Use for determining damage levels on specific structures

See also FEMA's journal of mitigation planning and actions related to Harvey [8].

References and related links: [1] FEMA_Depths_3m_v3.zip (39 gb ftp download) [https://data.femadata.com/Region8/Mitigation/Data_Share/] [2] TACC 39gb wget or ftp download [https://web.corral.tacc.utexas.edu/nfiedata/Harvey/flood_data/FEMA_Harvey_Depths_3m.gdb.zip] [3] FEMA map viewer for Hurricane Harvey resources (flood depths is bottom selection in layers list) [https://fema.maps.arcgis.com/apps/webappviewer/index.html?id=50f21538c7bf4e08b9faab430bc237c9] [4] FEMA NHRAP ftp [https://data.femadata.com/FIMA/NHRAP/Harvey/] [5] [https://data.femadata.com/FIMA/NHRAP/Harvey/Harris_AOIandBoundaries.zip] [6] [https://data.femadata.com/FIMA/NHRAP/Harvey/Harris_Mosaic_dgft.zip] [7] [https://data.femadata.com/FIMA/NHRAP/Harvey/Rockport_DG_unclipped.zip] [8] Hurricane Harvey Mitigation Portfolio - FEMA map journal [https://fema.maps.arcgis.com/apps/MapJournal/index.html?appid=70204cf2762d45409553fd9642700b7f]

LiDAR grid coverage for the 2018 product (Full Extent).