Related by context. All words. (Click for frequent words.) 63 streamside habitat 62 irrigate farmland 61 silvery minnow 60 Rio Grande silvery minnow 60 endangered suckers 59 recharge groundwater 59 riparian corridors 59 instream flows 58 brook trout habitat 58 riparian habitats 58 threatened coho salmon 58 recharge underground aquifers 57 Elephant Butte Reservoir 57 migratory bird habitat 57 Chiricahua leopard frogs 57 endangered mussels 57 imperiled salmon 57 aquatic biodiversity 57 acequias 57 recharging groundwater 57 threatened Delta smelt 57 native westslope cutthroat 56 Bolson tortoise 56 endangered chinook salmon 56 San Juan Chama 56 storm drains unclogged 56 transmountain diversions 56 dams spillways 56 humpback chub 56 Environmental Quality Incentive Program 56 backwater lakes 56 estuarine habitats 56 native cutthroat trout 56 endangered jaguars 55 endangered pallid sturgeon 55 thirsty Front Range 55 Umatilla Basin 55 migratory bird habitats 55 nongame animals 55 brackish groundwater 55 playa lakes 55 Wildlife refuges 55 threatened delta smelt 55 wetlands floodplains 55 elk feedgrounds 55 endangered arroyo toad 55 southwestern willow flycatcher 54 watersheds 54 Klamath basin 54 silvery minnows 54 desert tortoise habitat 54 juvenile salmonids 54 speckled dace 54 riparian forest 54 Brackish water 54 Yuma clapper rail 54 vernal pool species 54 Pallid sturgeon 54 bays estuaries 54 wetland ecosystems 54 desert pupfish 54 Klamath irrigators 54 Deschutes Basin 54 irrigating crops 54 salt marsh habitat 54 Cutthroat trout 54 floodplains wetlands 54 Perins Peak 54 aquifer recharge 53 rangeland grasses 53 Moapa dace 53 Mississippi Alluvial 53 aquatic grasses 53 vernal pool habitat 53 nutrient inputs 53 Saltcedar 53 SWCDs 53 nonnative trout 53 Gila chub 53 reintroduce wolves 53 coldwater streams 53 Santa Ana sucker 53 mule deer habitat 53 irrigate parched 53 bighorn habitat 53 summering grounds 53 riverways 53 Prolonged droughts 53 drift eastward 53 Peninsular bighorn sheep 53 westslope 53 steelhead smolts 53 Chenier Plain 53 Snake River steelhead 53 sage grouse mule deer 53 salmon Delta smelt 53 irrigate crops 53 Hueco Bolson 53 resacas 53 tortoise habitat 53 Colorado pikeminnow 53 vaquita 53 caribou calving grounds 53 endangered salmon 52 trout hatcheries 52 kokanee trout 52 Upper Klamath Basin 52 Cheoah River 52 coastal bays 52 Salton Sea restoration 52 waterfowl habitat 52 Arctic grayling 52 Fryingpan Arkansas 52 Streamflows 52 wintering elk 52 streamside vegetation 52 nesting waterfowl 52 saline intrusion 52 pelicans turtles 52 recharge basins 52 riparian ecosystems 52 Treated wastewater 52 nonfederal lands 52 waterfowl habitats 52 razorback suckers 52 Little Assawoman Bay 52 freshwater streams 52 boreal caribou 52 forested watersheds 52 saltcedar leaf beetles 52 streambanks 52 graze livestock 52 Southwestern willow flycatcher 52 nesting habitats 52 raw sewage discharges 52 McClusky Canal 52 shrub steppe 52 aquatic fauna 52 Chattahoochee Flint 52 sagebrush ecosystem 52 endangered coho salmon 52 coaster brook trout 52 Wetland Reserve 52 freshwater impoundments 52 Porcupine Caribou Herd 52 stockwater 52 compensatory mitigation 51 warmwater fish 51 voracious invasive species 51 overappropriated 51 bottomland hardwood forests 51 Scrub jay 51 coldwater fisheries 51 Portneuf River 51 freshwater delta 51 endangered Delta smelt 51 instream flow 51 upstream reservoirs 51 tamarisk removal 51 snail kite 51 grassland ecosystem 51 instream 51 irrigational facilities 51 Gambusia affinis 51 degraded ecosystems 51 giant garter snake 51 Act NAWCA 51 tiny delta smelt 51 Upper Floridan Aquifer 51 salmon spawning grounds 51 Yellowstone cutthroat trout 51 wild brook trout 51 Sarapiqui 51 shorebird habitat 51 roundtail chub 51 endangered wood stork 51 freshwater canals 51 nonnative invasive 51 Lahontan cutthroat 51 filter impurities 51 Abundant rainfall 51 removing contaminated sediments 51 rivers 51 oceans coasts 51 CALFED 51 grow yerba mansa 51 Upper Floridan aquifer 51 Sourlands 51 Atchafalaya River Basin 51 westslope cutthroat trout 51 Topeka shiner 51 inland fisheries 51 bighorn sheep herds 51 endangered Chinook salmon 51 riparian zones 51 forest meadows shrub 51 seawater intrusion 51 threatened Lahontan cutthroat 51 grasslands wetlands 51 Bonny Reservoir 51 streamside forests 51 irrigations systems 51 livestock herders 51 river basin 51 Snake River salmon 51 Lahontan Cutthroat Trout 51 Gangetic dolphin 51 prairie potholes 51 pike minnow 51 streambank 51 wintering habitat 51 arid grasslands 51 degraded soils 51 mountain plovers 51 Xe Bang Fai 51 northern leopard frogs 51 waterfowl refuges 51 riparian ecosystem 50 Quino checkerspot butterfly 50 sandpipers plovers 50 Cochiti Dam 50 overflown creeks 50 Cheesman Reservoir 50 prairies wetlands 50 Wodder 50 wildlife habitat 50 watchable wildlife 50 bog turtle habitat 50 tallgrass prairies 50 cottonwood willow 50 snail kites 50 Controlled burns 50 migratory flyway 50 Reserve Enhancement 50 brackish marshes 50 Iao aquifer 50 shortgrass prairie 50 steelhead spawning 50 migrating salmon 50 riparian restoration 50 delicate ecosystems 50 quail habitat 50 vegetated buffers 50 Gunnison Sage grouse 50 fluvial arctic grayling 50 undeveloped shoreline 50 sturgeon striped bass 50 tributary streams 50 haors 50 wetland ecosystem 50 Attwater Prairie Chicken 50 grassland habitats 50 Roadless areas 50 wildife 50 endangered steelhead trout 50 Lajas Valley 50 oysters shrimp crabs 50 Firebreaks 50 agro pastoralist 50 migratory shorebirds 50 transmountain 50 upland habitats 50 overexploit 50 agro biodiversity 50 Cutthroat Trout 50 Invasive mussels 50 grasshopper populations 50 Alviso Slough 50 replenish aquifers 50 semiarid climate 50 wolves grizzly bears 50 Alluvial Aquifer 50 Arahuay lone industry 50 desalinate brackish 50 Sparta aquifer 50 grassland ecosystems 50 San Bernardino kangaroo rat 50 groundwater aquifer 50 Galapagos volcano erupts 50 depleting aquifers 50 sturgeon spawning 50 riparian habitat 50 Oliver Wanger 50 sedimentation basins 50 acequia 50 Bahia Grande 50 Pedery 50 swamps marshes 50 Fenholloway 50 headwater stream 50 nesting beaches 50 pollinator habitat 50 Grass carp 50 backwater sloughs 50 Brushy Lake 50 threatened desert tortoise 50 Trans Pecos region 49 wetland riparian 49 Mokelumne River watershed 49 incidental bycatch 49 scrub shrub 49 intertidal marsh 49 eroding shorelines 49 Klamath salmon 49 Siltation 49 Beas rivers 49 Ossipee Pine Barrens 49 wetlands flood plains 49 nonconsumptive 49 wolves grizzlies 49 Tar Pamlico 49 Peconic Estuary 49 Mexican garter snake 49 groundwater aquifers 49 phosphorus pollution 49 bottomland forests 49 Cottontails seek 49 parks greenbelts 49 Putah 49 dammed rivers 49 freshwater habitats 49 brooks streams 49 Ogallala aquifer 49 condor sanctuary 49 bioenergy feedstocks 49 Everglades headwaters 49 aerial pesticide spraying 49 porpoise vaults 49 stingless wasps 49 LINCOLN PARK LAKE DFG 49 walleye stocking 49 Natomas Basin 49 invasive zebra mussels 49 irrigated agriculture 49 Rio Grande cutthroat trout 49 Excess nutrients 49 habitat 49 salt cedars 49 upper Fryingpan 49 amphibian habitat 49 longleaf pine forests 49 reproduce prolifically 49 Kiamichi River 49 aquatic habitats 49 macro invertebrate 49 Mhadei river 49 tributary rivers 49 Mainstem 49 highly erodible land 49 white sided jackrabbit 49 grassland habitat 49 Chiquibul 49 Granby Reservoir 49 spot tailed earless 49 turtle nesting beaches 49 ravenous carp 49 Fryingpan Arkansas Project 49 streambank erosion 49 razorback sucker 49 prairie grasslands 49 black capped vireo 49 Fisheating Creek 49 Ocklawaha rivers 49 Waikamoi 49 longleaf pine ecosystem 49 piping plover shorebird 49 tarplant 49 riparian wetland 49 Sonoran pronghorn 49 Sul Santa Catarina 49 blue heron rookery 49 Caura River 49 woodland grassland 49 upland meadows 49 Tustumena Lake 49 spawning habitat 49 walleyes crappies 49 stream buffers 49 tidal marshes 49 Stephens kangaroo rat 49 freshwater sawfish 49 Pecos Wilderness 49 Fork Flathead 49 Imnaha River 49 salmon steelhead 49 Bobwhite quail 49 nonpotable 49 lesser prairie chickens 49 aquacultural 49 anadromous fish 49 native Yellowstone cutthroat 49 pheasants quail 49 irrigable lands 49 mixed conifer forests 49 Dworshak Reservoir 49 Hylebos Creek 49 Drenching storms 49 endangered Steller sea lions 49 National Wildlife Refuges 49 gambusia 49 mussel species 49 Pasig Marikina 49 contaminates drinking 49 silted rivers 48 spikedace 48 Snake River basin 48 cui ui 48 unroaded 48 Hydroelectric dams 48 dune lakes 48 bogs swamps 48 Carmans River 48 Cabeza Prieta 48 Gunnison Sage Grouse 48 Pecos sunflower 48 polar bears seals 48 Carrizo Wilcox Aquifer 48 fertilizing lawns 48 Nicole Rosmarino WildEarth Guardians 48 Snake Plain Aquifer 48 reclaimed wastewater 48 Underwater grasses 48 dryland farmers 48 wintering ducks 48 waterfowls 48 coastal estuaries 48 polluted stormwater runoff 48 Overflowing rivers 48 replanting forests 48 Carol Rushin 48 wetland habitats 48 renourish beaches 48 Tenmile Creek 48 endangered porpoise 48 Bonneville cutthroat trout 48 Valles Caldera National 48 endangered piping plovers 48 Zebra mussel 48 hatchery coho salmon 48 Yolo Bypass 48 wetland vegetation 48 Roger Pulwarty 48 Hells Canyon dams 48 Neuse River basin 48 Seminoe Mountains 48 culling herds 48 tidal inlets 48 vaquita porpoise 48 Delta Smelt 48 Spotted owl 48 riparian vegetation 48 Biscayne Aquifer 48 grazing permittees 48 LNG siting 48 hatchery reared fish 48 fishable waters 48 Chairman Russell Kokubun 48 Threadfin shad 48 Izembek 48 pine savanna 48 planktons 48 Yellowstone cutthroat 48 bonytail 48 reintroducing lynx 48 riparian forests 48 nutria ate 48 Hal Candee senior 48 whitewater boating 48 spawning habitats 48 Snake River Basin 48 blackbird baiting 48 mysis shrimp 48 Multi Species 48 ecologically sensitive areas 48 forested lands 48 Hine emerald dragonfly 48 nesting bald eagle 48 quail pheasant 48 phosphorous discharges 48 irrigation shutoffs 48 Ozark Aquifer 48 gnatcatchers 48 Karen Guz 48 Rio Conchos 48 groundwater basins 48 bottomland hardwood 48 transmountain water 48 Prewitt Reservoir 48 Fry Ark 48 saltwater estuaries 48 Nariva Swamp 48 PacifiCorp dams 48 Lake Fastrill 48 Odessa Subarea 48 Vast stretches 48 endangered leatherback turtles 48 sandy bottomed 48 Matamoros Reynosa 48 Sevilleta National 48 artificial burrows 48 Maurepas Swamp 48 salmon hatcheries 48 streambank stabilization 48 river basins 48 River basin 48 Yadkin Pee Dee 48 endangered red cockaded 48 Ugum 48 Wine grape growers 48 migrating flock 48 spokeswoman Susan Siravo 48 Gunlock Reservoir 48 reservoirs 48 Banklick Creek 48 groundwater depletion 48 Vernal pools 48 aquaculture ponds 48 damming rivers 48 water 48 Nassau Grouper 48 nutrient runoff 48 desalinating sea water 48 Longleaf pine 48 smallholder farming 48 Elizabeth Slown spokeswoman 48 marine estuarine 48 Kittitas Yakima 48 Vallecito Reservoir 48 wetland restorations 48 Paiute cutthroat trout 48 western snowy plover 48 nonindigenous 48 brook lamprey 48 Rio Grande bosque 48 mussel infestation 48 shallow aquifers 48 refugia 48 Napindan Channel 48 boreal toad 48 downstream Kotri 48 westslope cutthroat 48 neotropical migratory birds 48 Aquatic Preserve 48 PROSSER LAKE 48 Conneaut Creek 47 cypress domes 47 cypress tupelo 47 boreal toads 47 woodland habitats 47 Overfishing pollution 47 upland habitat 47 nonpoint source 47 Koocanusa Reservoir 47 Seagrasses 47 nonnative fish 47 Landowner Incentive Program 47 migratory corridors 47 cougars wolves 47 nonpoint pollution 47 nearshore marine 47 Pantabangan Dam 47 riparian corridor 47 cattail marshes 47 walrus polar bears 47 rivers estuaries 47 habitats 47 acquifer 47 estuarine habitat 47 delicate marshlands 47 endangered jaguar 47 pollute rivers 47 Jamie Pittock 47 catfish carp 47 Pristine habitat 47 Greater Sage Grouse 47 livestock rearing 47 semiarid 47 recharges groundwater 47 riparian buffer 47 Rotational grazing 47 early successional forest 47 overharvested 47 Pymatuning Reservoir 47 foraging habitats 47 Floods engulf 47 endangered delta smelt 47 polar bears caribou 47 wildlife corridors 47 irrigable 47 willow shrubs 47 streamside buffers 47 Calico Mountains 47 gillnet fisheries 47 tiger salamanders 47 interbasin transfers 47 predator prey relationships 47 riparian 47 roadless forest 47 eradicate bovine tuberculosis 47 Uncompahgre River 47 replenishing groundwater 47 Nassawango Creek 47 dams 47 endangered Sonoran pronghorns 47 Ecosystem Restoration 47 riparian plantings 47 degraded forests 47 crop pollination 47 Anaktuvuk 47 Puget Sound chinook salmon 47 mountain plover 47 waterbodies 47 piñon juniper 47 fishways 47 Venezuela expropriates 47 btwn Spinney 47 river drainages 47 freshwater estuaries 47 Warmer wetter weather 47 Sierra snowmelt 47 Subsistence farmers 47 ecologically sensitive lands 47 Yakama Reservation 47 leaky septic tanks 47 woodlands wetlands 47 waterways 47 Rebecca Wodder president 47 Malpai Borderlands Group 47 rocky intertidal 47 threatened piping plover 47 Jarbidge River 47 endangered woodland caribou 47 biodiverse ecosystems 47 Batten Kill trout 47 Lake Kaweah 47 woodrats 47 Tijuana Estuary 47 spawning tributaries 47 shrub steppe habitat 47 Rio Grande Conservancy 47 Pupukea Paumalu 47 migratory pathway 47 cormorant populations 47 Warmer seas 47 Robert Cullick 47 waterfowl shorebirds 47 brown trout fishery 47 endangered amphibians 47 mayflies stoneflies 47 native flora 47 wetland restoration 47 wildlife habitats 47 conserve biodiversity 47 groundwater replenishment 47 fringe toed lizard 47 acid sulfate 47 nitrogen leaching 47 undammed river 47 songbirds raptors 47 dunes sagebrush lizard 47 LAKE OROVILLE 47 Ganga basin 47 sink boreholes 47 aquatic insect 47 conservation 47 Emiquon 47 Wacissa 47 Groundwater Basin 47 dredge canals 47 Maya Biosphere Reserve 47 Abajo Mountains 47 mule deer herds 47 tidal estuaries 47 FAR WEST TEXAS 47 CRP haying 47 hydroponic greenhouses 47 Warmer winters 47 nutrient leaching 47 Churro sheep 47 Picayune Strand 47 Khulna Satkhira 47 Captive breeding 47 Saltwater intrusion 47 Estancia Basin 47 freshwater aquifers 47 Pulangi River 47 mitigative 47 bighorn sheep habitat 47 polluted stormwater 47 Tehachapis 47 nutrient discharges 47 walleye spawning 47 Batiquitos Lagoon 47 bollworm eggs 47 Boll weevils 47 rainbow smelt 47 Beaver Creek Reservoir 47 erosion sedimentation 47 Blackland Prairie 47 Wildfires ravage 47 shorelands 47 Elephant Butte Irrigation 47 shad herring 47 endangered songbird 47 Giant Salvinia 47 shortnose sturgeon 47 Sutlej rivers 47 Head Start preschools 47 endangered Peninsular bighorn 47 Blanding Turtle 47 Dryland wheat 47 Basin hydroelectric dams 47 Lesotho Malawi Mozambique Namibia 47 coldwater fish 47 voracious feeders 47 spawning kokanee 47 aquatic habitat 47 Pumalin 47 woodlands grasslands 47 valley elderberry longhorn beetle 47 upland sandpipers 47 aquatic ecosystem 47 reusing wastewater 47 greenback cutthroat trout 47 blufflands 47 migrating southward 47 salamander habitat 47 emergent vegetation 47 irrigated farmland 47 Storm drenches 47 adversely modify 47 vole populations 47 Treasured Landscapes 47 voracious filter feeders 47 presettlement 47 Alligator gar 47 bottomland hardwood forest 47 Zooplankton 47 Judge Oliver Wanger 47 Tamugan 47 Ute Reservoir 47 Gopher tortoise 47 Vilcanota river 47 intensively cultivated 47 irrigation ditches 47 tamarisks 47 whitewing 47 Valles Caldera 47 rainfed agriculture 47 bottomland hardwoods 47 groundwater recharge 47 robbing algae blooms 47 Mosquitoes breed 47 Sparta Aquifer 47 larval mosquitoes 47 Jeffrey Steenson 46 irrigated crops 46 hay meadows 46 phosphorus discharges 46 aquifer depletion 46 Tinkers Creek 46 Alpaca savage beating 46 tributaries 46 aquatic invertebrates 46 Sullys Hill 46 Watershed Partnership 46 coho chinook 46 Thurmond Dam 46 Fanged frog 46 Klamath Reclamation Project 46 Cuu Long Mekong 46 fix leaky pipes 46 Fecal contamination 46 nonnative grasses 46 freshwater marsh 46 soil moistures 46 rainbow trout fishery 46 merchant Mamoru Saito 46 herring shad 46 CRMWD 46 salamanders frogs 46 salty soils 46 Soil moisture levels 46 wild ungulates 46 recharging aquifers 46 Woodland Caribou 46 Apalachicola Chattahoochee 46 fecal coliform contamination 46 threatened woodland caribou 46 Program WRP 46 eat mosquito larvae 46 warmwater 46 Elephant Butte Dam 46 wetland ecology 46 Bayou D' Arbonne 46 Lagunitas Creek 46 irrigated pastures 46 re vegetate 46 oak savannahs 46 endangered manatees 46 Glendo Reservoir 46 Warm Springs Dam 46 Ferry Reservoir 46 abalone fishery 46 endangered condors 46 jaguar habitat 46 sprayfield 46 Great Ruaha 46 populous Front Range 46 RICD 46 naturally occurring radium 46 molluscs crustaceans 46 hydrology geology 46 Bayou Manchac 46 infertile soils 46 forests meadows 46 spineflower 46 Mongabay How 46 cactus ferruginous pygmy owl 46 homemade dipnetting pole 46 groundfish fisheries 46 Ewaso Nyiro 46 Caloosahatchee estuary 46 Bolinas Lagoon 46 yellow legged frogs 46 Porcupine caribou herd 46 pristine woodlands 46 golden cheeked warbler 46 elk bighorn sheep 46 bathing washing 46 waterfowl biologists 46 Usangu 46 saline groundwater 46 Veterinarian Dustin Odekoven 46 Lake Maumelle 46 drought striken 46 Jhum cultivation 46 marine finfish 46 migratory seabirds 46 Sisquoc River 46 Tropical rainforests 46 ranchers 46 tepary beans 46 Hulah 46 Uncompahgre Plateau 46 subwatershed 46 wetland habitat 46 sturgeon fishery 46 Freshwater mussels 46 mule deer herd 46 effluent reuse 46 Wayne Gieselman 46 squawfish 46 Brahmaputra rivers 46 mussel larvae 46 upland forests 46 hydrologically connected 46 refuges 46 frogs salamanders 46 steelhead hatchery 46 deforestation desertification 46 windswept slopes 46 wetlands prairies 46 forage 46 deforesting 46 mussel populations 46 overpumped 46 wet meadows 46 grasshopper sparrow 46 huntable populations 46 UNION VALLEY RESERVOIR 46 endangered ocelot 46 raccoons coyotes 46 Camanche Reservoir 46 dryland agriculture 46 Feral swine 46 vernal ponds 46 McPhee Reservoir 46 undammed rivers 46 genetically modified beets 46 Rialto Colton 46 Alameda whipsnake 46 Unami Creek 46 elk reintroduction 46 Albemarle Pamlico 46 fat threeridge mussel 46 Upcountry reservoirs 46 mainstem Umpqua 46 Inland Bays watershed 46 caribou populations 46 tributary creeks 46 brook trout populations 46 red legged frogs 46 unfragmented forest 46 Contaminated groundwater 46 pesticide Furadan 46 Odessa aquifer 46 fingerling trout 46 Equus Beds aquifer 46 warmwater species 46 threatened steelhead trout 46 dig burrows 46 maleo 46 Cattle ranchers 46 Chihuahuan Desert 46 coldwater species 46 biologically diverse ecosystems 46 groundwater withdrawals 46 Shoal Lakes 46 Longfin smelt 46 Soil erosion 46 parks wildlife refuges 46 overcrowded unsanitary 46 chinook salmon steelhead 46 grazing pastures 46 Silverwood Lake 46 sagebrush habitat 46 brood rearing 46 Delaware Estuary 46 Arctic Caribou Herd 46 orchards vineyards 46 variable milfoil 46 Birders flock 46 seabird nesting 46 Todd Malmsbury 46 Sluice gates 46 Tauranga Taupo 46 lampricide 46 Arapaho Roosevelt 46 BOCA LAKE 46 waterfowl populations 46 Allatoona Lake 46 lifestock 46 azure Persian Gulf 46 suggested desalinating sea 46 Hickory Aquifer 46 saguaro fruit 46 semi arid regions 46 trout fingerlings 46 salt marsh ecosystem 46 Loch Lomond Reservoir 46 Mkomazi 46 hatchery trout 46 nongame fish 46 roadless backcountry 46 irrigable land 46 dams weirs 46 Pygmy rabbits 46 red cockaded woodpeckers 46 goat herds 46 freshwater wetland 46 nonmotorized trails 46 Chirikof Island 46 Hanford Reach 46 Owyhee Canyonlands 46 Program EQIP 46 groundwater recharging 46 NPDES permits 46 Irrigated agriculture 46 Artificial reefs 46 Prescribed burn 46 Incentive Program WHIP 46 Winds howled 46 delist gray wolves 46 fescue pastures 46 pygmy owls 46 wild bighorns 46 nutrient deficient 46 Least terns 46 Idaho Owyhee Canyonlands 46 phosphorus runoff 46 wetland soils 46 riparian buffers 46 Bhima river 46 desalinating 46 Rapidan rivers 46 phosphogypsum stacks 46 gopher frogs 46 spawning walleyes 46 native freshwater mussels 46 Obleski 46 Sea otters 46 rangelands 46 streambank restoration 46 loach minnow 46 highly erodible 46 Lotus Vermeer 46 Kokanee salmon 46 creeks rivers 46 irrigated cropland 46 overabundant deer 46 Bayou Sauvage 46 Blacktail Creek 46 bighorn sheep herd 46 Mahadayi 46 Ninemile Creek 46 nonnative mussels 46 cyanobacterial blooms 46 aquifers