| 
                                    
                                        gptkbp:instanceOf
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:reservoir
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:alsoKnownAs
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:High_Plains_Aquifer
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:area
                                    
                                 | 
                                
                                    
                                        
                                            
                                            about 174,000 square miles
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:contains
                                    
                                 | 
                                
                                    
                                        
                                            
                                            freshwater
                                        
                                        
                                         
                                    
                                        
                                            
                                            sand, gravel, clay, silt
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:firstMapped
                                    
                                 | 
                                
                                    
                                        
                                            
                                            1898
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:governedBy
                                    
                                 | 
                                
                                    
                                        
                                            
                                            state water laws
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:importantFor
                                    
                                 | 
                                
                                    
                                        
                                            
                                            critical for U.S. agriculture
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:locatedIn
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Colorado
                                        
                                         
                                    
                                        
                                            gptkb:Kansas
                                        
                                         
                                    
                                        
                                            gptkb:Nebraska
                                        
                                         
                                    
                                        
                                            gptkb:New_Mexico
                                        
                                         
                                    
                                        
                                            gptkb:Oklahoma
                                        
                                         
                                    
                                        
                                            gptkb:South_Dakota
                                        
                                         
                                    
                                        
                                            gptkb:Texas
                                        
                                         
                                    
                                        
                                            gptkb:United_States
                                        
                                         
                                    
                                        
                                            gptkb:Wyoming
                                        
                                         
                                    
                                        
                                            gptkb:Great_Plains
                                        
                                         
                                    
                                        
                                            gptkb:Eastern_Colorado
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:mainRechargeSource
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:precipitation
                                        
                                         
                                    
                                        
                                            
                                            surface water infiltration
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:majorCitiesAbove
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Midland
                                        
                                         
                                    
                                        
                                            gptkb:Odessa
                                        
                                         
                                    
                                        
                                            gptkb:Amarillo
                                        
                                         
                                    
                                        
                                            gptkb:Dodge_City
                                        
                                         
                                    
                                        
                                            gptkb:Garden_City
                                        
                                         
                                    
                                        
                                            gptkb:North_Platte
                                        
                                         
                                    
                                        
                                            gptkb:Lubbock
                                        
                                         
                                    
                                        
                                            
                                            Liberal
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:managedBy
                                    
                                 | 
                                
                                    
                                        
                                            
                                            local and state agencies
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:maximumDepth
                                    
                                 | 
                                
                                    
                                        
                                            
                                            ranges from a few feet to over 1,000 feet
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:namedAfter
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:Ogallala,_Nebraska
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:notableFeature
                                    
                                 | 
                                
                                    
                                        
                                            
                                            one of the world's largest aquifers
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:partOf
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:High_Plains_Aquifer_System
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:providesWaterFor
                                    
                                 | 
                                
                                    
                                        
                                            
                                            drinking water
                                        
                                        
                                         
                                    
                                        
                                            
                                            irrigation
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:receivesWaterFrom
                                    
                                 | 
                                
                                    
                                        
                                            
                                            over 2 million people
                                        
                                        
                                         
                                    
                                        
                                            
                                            one-fifth of U.S. irrigated farmland
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:rechargeRate
                                    
                                 | 
                                
                                    
                                        
                                            
                                            very slow
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:rechargeTime
                                    
                                 | 
                                
                                    
                                        
                                            
                                            thousands of years
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:studiedBy
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:U.S._Geological_Survey
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:threats
                                    
                                 | 
                                
                                    
                                        
                                            
                                            climate change
                                        
                                        
                                         
                                    
                                        
                                            
                                            declining water levels
                                        
                                        
                                         
                                    
                                        
                                            
                                            over-extraction
                                        
                                        
                                         
                                    
                                        
                                            
                                            agricultural use
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:volume
                                    
                                 | 
                                
                                    
                                        
                                            
                                            estimated at about 2,900 cubic kilometers
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:waterLevelDecline
                                    
                                 | 
                                
                                    
                                        
                                            
                                            up to 150 feet in some areas
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:形成时期
                                    
                                 | 
                                
                                    
                                        
                                            
                                            Miocene to Pliocene
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:bfsParent
                                    
                                 | 
                                
                                    
                                        
                                            gptkb:western_Kansas
                                        
                                         
                                    
                                        
                                            gptkb:Amarillo,_Texas,_United_States
                                        
                                         
                                    
                                        
                                            gptkb:High_Plains
                                        
                                         
                                    
                                        
                                            gptkb:Sandhills
                                        
                                         
                                    
                                        
                                            gptkb:Llano_Estacado
                                        
                                         
                                    
                                        
                                            gptkb:Keystone_XL_Pipeline
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        gptkbp:bfsLayer
                                    
                                 | 
                                
                                    
                                        
                                            
                                            6
                                        
                                        
                                         
                                    
                                 | 
                            
                        
                            
                                | 
                                    
                                        https://www.w3.org/2000/01/rdf-schema#label
                                    
                                 | 
                                
                                    
                                        
                                            
                                            Ogallala Aquifer
                                        
                                        
                                         
                                    
                                 |