Harris - Galveston Subsidence District

Transcription

1 Harris - Galveston Subsidence District History of Subsidence, Regulation, and Water Management in the Houston Region Michael J. Turco - General Manager ASSOCIATION OF WATER BOARD DIRECTORS GUEST LECTURE APRIL 22, 2016 HOUSTON, TEXAS

2 Outline Brief History of Subsidence Hydrogeology of the Gulf Coast and Subsidence History of the District Regulatory Plan Regulatory Plan successes Regulatory area three conversion requirements Water Conservation and the Path Forward

3 What is Subsidence? Subsidence is the lowering of the elevation of land surface over time. Subsidence can have a wide range of consequences depending on the location of the occurrence and its proximity to surface drainage and coastal zones In this area, clay compaction resulting from groundwater withdrawal is the primary cause for subsidence

4 Permanent Inundation due to Subsidence Goose Creek Oil Field Nearly 3 feet of subsidence occurred due to shallow fluid withdrawal. Today, remnants exist in San Jacinto Bay as much of the field has been inundated.

5 Hydrogeology

6 Mechanism for subsidence in the Gulf Coast

7 Subsidence has consequences

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10 Brownwood

11 Brownwood

12 Brownwood

13 HGSD 1976 Regulatory Areas Area of Concentrated Emphasis (ACE) Wells within the Area of Concentrated Emphasis (the ACE) were required to search for alternative supplies to groundwater. If an alternative supply existed, permittees were required to reduce their groundwater pumpage.

14 HGSD 1985 Regulatory Areas Area 1: 90% GW reduction by 1990 Area 2: 80% GW reduction by 1990 Area 3: 80% GW reduction by 1995 Area 4: 80% GW reduction by 2000 Area 5: 80% GW reduction by 2000 Area 6: 80% GW reduction by 2005 Area 7: 80% GW reduction by 2010 Area 8: no reduction required 1

15 HGSD 1992 Regulatory Areas Area 1: 10% groundwater Area 2: 20% groundwater Area 3: 80% GW reduction by 1995 Area 4: 80% GW reduction by 2002 Area 5: 80% GW reduction by 2005 Area 6: 80% GW reduction by 2010 Area 7: 80% GW reduction by

16 HGSD 1999 Regulatory Areas 3 2 1

17 Key Elements Regulatory Plan Areas 1 & 2 - Converted Area 1 GW reduced to 10% or less of TWD Area 2 GW reduced to 20% or less of TWD Area 3 Reduce GW pumpage by 30% by 2010 Reduce GW pumpage by 70% by 2020 Reduce GW pumpage by 80% by Exemptions: Agricultural Irrigation & Economic Hardships GRPs were due in 2003: 4 main Area 3 GRPS (Houston, NHCRWA, WHCRWA & CHCRWA) Disincentive Fee currently set at $5.00 / 1,000 gallons

18 Brownwood

19 2013 Regulatory Plan Update Utilized data from the 2010 Census and Annual Water-Level and Subsidence Data collected by the USGS and the Subsidence District Cooperative project between both Subsidence Districts and the Lone Star Groundwater Conservation District Brought together a group of consultants to help develop the plan: Metro Study and University of Houston: Conducted population projections and migration prediction Scott Marr (Fugro): Updated multiple local scale analytical subsidence models in the Houston Region Mark Kasmarek (USGS): Updated the regional groundwater flow model John Seifert (LBG-Guyton): Technical expertise and developed the predictive model data sets Mike Reedy (Freeze and Nichols): Project Manager and Regulatory Plan development Received additional input from the Texas Water Development Board

20 4,000,000 3,500,000 3,000,000 2,500,000 2,000,000 1,500,000 1,000, ,000 - POPULATION BY HGSD REGULATORY AREA 3,382,481 3,528,168 3,233,836 3,076,529 2,905,158 2,710,303 2,401,086 2,250,944 2,259,472 2,122,327 1,986,120 1,848,040 1,702,190 1,566, , , , , , , , HGSD_AREA_1 HGSD_AREA_2 HGSD_AREA_3

21 1 square mile grid

22 HGSD Area 3 Conversion Scenarios Scenario 1 (No Conversion After 2010) 30% Scenario 2 (Current Regulatory Plans) 30% 70% 80% Scenario 3 30% 60% 80% Scenario 4 30% 55% 80%

23 Harris-Galveston Subsidence District Regulatory Plan Updated in 2013 Areas 1 and 2 Fully Converted Area 1 GW Reduced to 10% or less of TWD Area 2 GW Reduced to 20% or less of TWD Area 3 GW Reduced to 70% or less of TWD 2010 GW Reduced to 40% or less of TWD 2025 GW Reduced to 20% or less of TWD 2035 Exemptions: Agricultural Irrigation Non compliance subject to disincentive fee = $7.00/1,000 gallons 3 2 1

24 Regulating groundwater to stop subsidence balancing needs, availability, and impact The Harris-Galveston and Fort Bend Subsidence Districts use regulatory plans and rules developed by each board to stop subsidence in the region. The regulatory approach is focused on the conversion of a portion of the Total Water Demand to an alternative source of water (Surface Water, Reuse, Brackish Desalination of Seawater, or others). Consideration is given to the availability of alternative sources, expected population growth, patterns of potential development, and predicted subsidence based on several hypothetical scenarios. Both the HGSD and FBSD Regulatory plans were updated in 2013.

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26 Evangeline Aquifer Water Level Change

27 HGSD Cooperative GPS Network

28 Future Water Supplies Luce Bayou Interbasin Transfer Project Raw water supply transfer from Trinity River to Lake Houston Northeast Water Purification Plant (NEWPP) Expansion -- Treated water supply from Lake Houston Transmission Lines from NEWPP Internal Distribution Systems Courtesy: City of Houston

29 More than just a regulatory plan Science and Research Desalination of brackish groundwater Aquifer Storage and Recovery Water Conservation Elementary School Program Outdoor Irrigation Campaign

30 Elementary School Program Update Students enrolled through February 2016: 50,042 (worth about 4.2 billion gallons of series B groundwater credits) January 2016 HGSD Water Detective Website revisions completed per District requirements February 2016 Conducted teacher focus group District documentation for the Water Smart recognition sent to sponsors Enrollment above average based on this time in previous years May 2016 Beta test of water conservation app there s an app for that now!

31 Elementary School Program Mobile Application

32 Outdoor Irrigation Campaign The campaign will focus on landscape irrigation, both residential and commercial Two primary components to the implementation WaterMyYard Program with Texas A&M University Installation of ET network and development of District specific webtools to educate and notify registered users on the best water management practices to ensure a vibrant landscape while conserving water Landscape Irrigation Best Management Practices Outreach and Media Working with other local entities (i.e. City of Houston, Water Authorities, MUDs, Municipalities), develop and disseminate similar messages across the District area. Unified message, unified purpose. Working with the water community to provide a focused effort.

33 Evapotranspiration Why does it matter? Evapotranspiration is the measure of two components of the water cycle: Transpiration use of water by plants Evaporation water loss due to phase shift from liquid to gas to the atmosphere ET is measured using multiple sensors and can be influenced by landscape vegetation, canopy, land-use and others. For the purpose of this project, a ET network will be established based on recommendations from Texas A&M with stations located at strategic partner secured facilities ET data will be communicated to the A&M database via cellular modem, District staff will maintain the network, with A&M providing technical guidance. ET data collected could also be used in the regulatory planning modelling efforts.

34 ET Network Stations

35 WaterMyYard

36 Summary and Conclusions Subsidence has been an issue in Houston area since the 1920s First documented link between shallow fluid withdrawal and aquifer compaction occurred in Goose Creek oilfield near Baytown, TX in 1929 Population increases following World War II caused a rapid increase in groundwater use and increased rates of subsidence throughout the region The District was created in 1975 and since that time has gone through several regulatory plan iterations. In 2013, based on hydrogeologic data and stakeholder input, future conversions dates were pushed out and the 2025 conversion requirement was reduced by 10%

37 Summary and Conclusions The District is consistently collecting data, monitoring subsidence, and preparing for the next evaluation of the regulatory plan Recent data suggest that 2010 predictions of subsidence in area 3 are valid The District continues to look forward with innovative Science and Research focused on potential future water strategies and the potential for contributing to subsidence Water Conservation will be a key component of everyone's future water management strategy. The District s outdoor irrigation program will address a wide-spread water conservation message working with many local entities.

38 Brownwood Natural Area

39 SERVING THE GULF COAST COMMUNITY SINCE 1975