GIS Applications Using DEMs for Water

This report discusses the implementation of GIS applications utilizing Digital Elevation Models (DEMs) for water management. It defines DEMs and their uses, particularly in hydrology, and outlines different types of DEMs such as regular square grids, TIN, and contours. The report highlights the importance of accurate DEMs for watershed modeling and flood forecasting. It references two projects using DEM data for river terrain models and drainage network delineation. The report recommends using SRTM 90m Digital Elevation Data and suggests verifying data with Google Earth images and World Bank water development data. It also acknowledges limitations of DEMs, including limited analysis possibilities and rigid data structures. The report concludes with a formal sign-off from the civil engineer to the project manager.

Running head: MEMO REPORT 1
MEMO
Student Name
Institution

MEMO REPORT 2
TO: John Raines, Project Manager
FROM: Student Name, Civil Engineer
DATE: Feb 1. 2018
SUBJECT: Implementation of GIS applications that utilize DEMs for water
You have recently handed me over as a civil engineer for the implementation of GIS
application that will utilize DEM for water. Given below are our recommendation and finding.
What is DEM?
DEM which is also known as Digital Elevation Model, it can generally be used to obtain
the geographical location, geographic parameters, morphometric variables or terrain related
information. In the mixture of other information related to space, the DEM is an imperative
database for geological examination or 3D video movement, (for example, fly-throughs). Diverse
georeferenced 3D items can be obtained and supplemented by a facilitate framework and can be
introduced as a 2D map or 3D point of view.
DEM is usually used to record bare-earth terrain, vegetation, and man-made facilities.
Types if DEM for Hydrologic Applications.
1. Regular Square Grids
2. TIN (Triangulated irregular networks)
3. Contours
For Watershed's hydrology modeling, it is important to have a very accurate and uniform
DEM. Only through the amalgamation of geographical data, land use information, rainfall, water
storage etc. is a possible forecast of water and river flooding.

MEMO REPORT 3
Two of the projects are based on this DEM data are
1. GIS techniques for creating river terrain models for hydrodynamic modeling and
flood inundation mapping (Merwade, Cook, & Coonrod, 2008)
2. Limitation of 90 m SRTM DEM in drainage network delineation using the D8
method—a case study in the flat terrain of Bangladesh. (Rahman, Arya, & Goel,
2010)
Recommendation and Limitation of DEM
1. SRTM 90m Digital Elevation Data: The project in Bangladesh used Shuttle Radar
Topography Mission or SRTM model, same can be used in our project to delineate the
network of water. (SRTM, 2018)
2. Verification of Data: For verification, we can use two types of referenced data.
a. Images from Google Earth (Google, Inc, 2008)
b. And the water development data from world bank (Water Use in the United
States, 2018)
Limitation
Lines
 Limited analyze possibility
 Limited Visualization
Altitude Matrix
 Rigid structure of Data & Limited Adaptation of topographic structure
Sincerely
Student Name