The Role of Modeled Available Groundwater in Local Regulation and State Planning Presented By Bill Mullican, PG., to the 2015 Texas Alliance of Groundwater Districts Groundwater Summit San Marcos, Texas
The Role of Modeled Available Groundwater in
Local Regulation and State Planning
Presented By Bill Mullican, PG.,to the
2015 Texas Alliance of Groundwater DistrictsGroundwater Summit
San Marcos, Texas
Groundwater
$300
$500
$400
$100
$200
9
How many major aquifers have
been designated in Texas?
199,000,000,000,000,001
According to a recent scientific study published by Johnson, McCarthy, and Jones, what is
the volume of groundwater, in AFY, available in Texas today?
6
How many acronyms using the letters A, G, and M can be utilized based on TWC Chapter 36?
GAM – Groundwater Availability ModelGMA – Groundwater Management AreaMAG – Modeled Available Groundwater
MGA – Modeled Groundwater ApplicationsAGM – Approved Groundwater Model, and
AMG – Attorneys for Modeled Groundwater
16 Planning Regions
11
Three Texas Water Plans Published since SB 1 in 1997Six prior to SB 1 (1961, 1968, 1984, 1990, 1992, and 1997)
Texas Water Code Chapter 16.053 (e) & (2-a)
(e) Each regional water planning group shall submit to the development board a regional water plan that:(2-a) is consistent with the desired future conditions adopted under Section 36.108 for the relevant aquifers located in the regional water planning area as of the date the board most recently adopted a state water plan under Section 16.051 or, at the option of the regional water planning group, established subsequent to the adoption of the most recent plan.
31 Texas Administrative Code Chapter 357.32 (d)
RWPGs shall use modeled available groundwater volumes for groundwater availability, as issued by the Board, and incorporate such information in its RWP unless no modeled available groundwater volumes are provided. Groundwater availability used in the RWP must be consistent with the desired future conditions as of the date the Board most recently adopted a state water plan or, at the discretion of the RWPG, established subsequent to the adoption of the most recent state water plan.
0
2,000
4,000
6,000
8,000
10,000
12,000
1 2 3 4 5 6 7 8 9 10
Years
Scenario 1 - Drought Demands vs. MAGS
Drought Water Demand
Average Historical Use
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 500
2,000
4,000
6,000
8,000
10,000
12,000
Scenario 2 - Pumping + New Strategy vs. MAG
Pumping Strategy
MAG = 10,000 AFY
• Pumping in Year 1 starts at 5,500 AFY and increases at a rate of 100 AFY for 50 years
• WMS = 1,000 AFY pumping starting in Year 1
• MAG = 10,000 AFY• Total pumping +
WMS =447,500• Excess MAG =
47,500 AF.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 500
100,000
200,000
300,000
400,000
500,000
600,000
Scenario 2 - Cumulative MAG vs Cumu-lative Pumping + WMS
Cumulative MAG Cumulative Pumping + WMS