GROUNDWATER RESOURCE MANAGEMENT

BRYAN ZHOU

GEOGRAPHY 385

December 16, 2014

SUMMARY

Groundwater is the most important freshwater resource available to the public. Most of the world depends on groundwater for the industry and agriculture, but this resource is easily neglected in the form of pollution (heavy metal, pesticide, and fertilize) and excessive withdrawal. Organic solvent is another type of pollution that comes from hydraulic fracking (a controversial method of extracting petroleum resource from rocks. Another major threat to groundwater resource is climate change. The Western United State is experiencing a drought and the demands for groundwater have been increasing for the past decade. Groundwater is replenished through the accumulation of precipitation over thousands of years. The process involves water infiltrating the ground through cracks, fractures, or pores and is then stored in an aquifer (permeable layer of rock consists of sand, silt, or gravel). A web map is created using ArcMap and Flexbuilder. The map consists of point feature representing the wells from Harris County, Texas, Geocoding Service, and a SDE feature class. The wells contain valuable information about the water quality and the water table. The Geocoding Service allows the user to locate residential address. The SDE feature class allows the user to update the existing wells or digitize new ones. Future improvement for this project includes adding more domains to the SDE feature class. The highway shields symbols need more clarity and it is left unfinished. The map could use pop-up windows that reveal the ID, water quality, and water level for each well. The water level table needs to be incorporated into the map. The water level table can be used to generate a graph that shows the changes in water level over time.

PURPOSE

The purpose of the map is to provide the public or an agency the ability to manage groundwater resources. The project consists of point features that represent the wells of Harris County, Texas. Each well has following information: geographic location, well depth, and water quality. The web map also displays the river, county boundary, major highways and roads. The published map employs two map services: Geocoding Service and Feature Service (Editing) from Spatial Database Engine (SDE) feature class. The geocoding service allows the user to locate the address of residents who file a water quality complaint. User can make note of the problem and determine if the water issue is related to a nearby well. Due to the ongoing drought, farmers are drilling for new sources of water. Oil companies are always searching for new sources oil and natural gas. The feature service allows the user to update the existing wells and digitize new wells.

METHOD

A geodatabase is created for this project. The Geodatabase contain the following data (Figure 1):

Figure 1:

The well empty point feature class (Figure 2), state shapefile, and the TimeSeries table (Figure 3) have been downloaded from Aquaveo website (http://www.aquaveo.com/).

Figure 2: empty well feature class

Figure 3: TimeSeries table

Texas Water Development Board

http://www.twdb.state.tx.us/groundwater/data/gwdbrpt.asp

Well data tableWater level tableWater quality table

All the data is in comma-delimited text file. The data is clean up using Access or Excel.

Create a new ArcMap document.

Data Frame: NAD_1983_StatePlane_Texas_South_Central_FIPS_4204_Feet

The ArcHydro Groundwater tool (AHGW) is used to import the state well number, latitude, longitude, and aquifer ID, land elevation, well type, and well depth from the well data table into the empty point feature class.

Header Type

state_well_number HydroCodelat_dec Ylong_dec Xaquifer_id1 AquiferCodeelev_of_lsd LandElevwell_type FTypewell_depth WellDepth

The well is symbolizes using the FType field.

In the attribute table, the HydroID is set to equal to the HydroCode (state well number). This will be used to perform a join operation.

AHGW tool is used to import the state well number, well depth elevation, and data into the TimeSeries table. TimeSeries table is used to make a graph that shows the change in water level vs time.

Header Type

State_well_number FeatureIDDepth_from_lsd TsValueDate_Time TsTime

A join operation is conduct between the well point feature class and the table. The water levels are in negative value and need to represent the elevation of the water table. From the TsValue_normarlized field, TsValue and Land Elevation are added together. The VarID is set to 1. The AHGW Make Time Series Statistic tool (Figure 4) is used to generate a new well feature class called Water Level. The new layer contains the average water level for each well. Not all the well will have this information, because some of wells have no data.

Figure 4: Make Time Series Statistics

The streets, highway, river, and county boundary data have been downloaded from The City of Houston website: http://mycity.houstontx.gov/home/cohgis.html

The layer zoom, label classes, and symbology are created for the Highway: Interstate, US route, and State (Figure 5 and 6). The ArcMap is published and all the layers are added to the web map in the operational layer setting. Imagery is set as a base map.

Figure 5

Figure 6

An US Dual Range Address Locator is created for the street feature class (Figure 7 and 8). The Address Locator is published to the web server.

Figure 7

Figure 8

A new point feature class is created in the Geog385 SDE geodatabase. The feature class is name New_Well (see below) with the same coordinates and projection as the rest of the data. The feature class has the following subtype: private, oil, and gas (Figure 9). The domain only has editor and comment field. More subtype and domains will be added in the future. The feature class is registered as versioned and with tracking editing enabled.

Figure 9

Add the feature class to ArcMap with the appropriate symbols and published it to the server (Figure 10).

Figure 10

The Well_SDE map is published in flex builder (Figure 11). The street, well, water level, river, highway, river, and boundary layers are added to the operational layers. The Zhou_web (MS) and Feature Server (FS) of the SDE feature class are added to the operational layers. The Edit and locator widgets are added to the web map under Widget setting. The rest endpoint from the published Geocoding Service (Figure 12) is copy and pasted into the Locator URL.

Navigation setting is set on and adds a new title to map

Figure 11

Save the map and empty the cache.

Figure 12

Finish

DIFFICULITY

The most difficult part of this project is processing all the groundwater data. The data is in comma-delimited text file. Many parts of the data have null value and dates in the data need to be concatenate in the right format (mm/dd/yyyy) before processing to the next step. Access or Excel is needed to clean up the data before it is used for the project. Another issue is to figure out how to display the water level table to the web. A pop-up window sounds like a good idea, but I don’t know how it is done. Choosing the symbology for the different well is frustrating. I look into the style preference and check Geology, and it contains dozen of complex sybmols. In the end, I stick with something simple. The last part is to get geocoding service to work. I have to look into the street attribute table and make sure it is dual range. I have made sure the locator widget has the URL from the published geocoding service. For the SDE Feature editing, I have made sure to choose the Map service (MS) and Feature Service (FS) folders for the operational layer.

DISCUSSION/CONCLUSION

In the beginning, I want to do well management web map for the state of California, but the information is mostly incomplete or non-existed. The map could have helped this state manage its groundwater resources more efficiently. The current drought is costing California billions of dollars. Many farmers are drilling for groundwater and withdrawing water at high rate with means of regulating it. Subsidence has occurred in some parts of the state as result of excessive pumping, which will lead to flooding. Texas has good groundwater data and it will serve as model for this project. The web map definitely need more work. The SDE feature class needs more domains and subtypes. The highway shields symbols need more clarity and it is left unfinished. The map could use pop-up windows that reveal the ID, water quality, and water level for each well. An important element is to find a way to incorporate the water level table to the web. The water level table can be used to generate a graph that shows the changes in water level over time.