Riverine Analysis

Northern Great Plains

Riverine Analysis

2013 Contents Overview 3 Aquatic Ecosystem Classification 3 Fish Species Richness 8 Ecological Condition Index 8 Analysis 9 Results 9 References 11 Appendix: Individual AES Types 13

2 analysis was not sufficient for evaluating the status Overview of aquatic systems; thus, the terrestrial analysis was Grasslands around the globe are among the least pro- complemented with this independent riverine analy- tected biomes, yet they provide important habitat for sis of the ecoregion. a diversity of species, as well as food, fuel, and fiber We were fortunate to discover that an in-depth, scien- to sustain human populations. The Northern Great tific study was completed for the Missouri River Ba- Plains ecoregion was chosen as one of World Wild- sin in 2010: A GAP Analysis for Riverine Ecosystems life Fund’s (WWF) 15 priority landscapes around the of the Missouri River Basin (Annis et al.). The study world due to its relative intactness, rich biodiversity, area of the GAP project covers nearly all of the U.S. and potential for conservation. portion of the Northern Great Plains Ecoregion (Fig- In 2004, WWF and partners published an assessment ure 1). Thus, we elected to use habitat and threats data of conservation opportunities in the Northern Great from the already-completed project instead of start- Plains ecoregion, entitled Ocean of Grass, which ing anew. Because the species distribution data used has guided the work of many organizations over the in the GAP analysis was non-shareable, we comple- past decade. However, the landscape has changed in mented the data with distribution data for 16 species many ways since data were gathered for the previous derived from a combination of NatureServe G1-G3 assessment. In 2012, we reassessed the ecoregion, listed species, endemic, keystone and focal species collecting up-to-date information on wildlife distri- (as listed in Forrest et al. [2004] and TNC [1999]; bution, geography, demographics, climate change, focal species identified by senior-level WWF staff). and threats. We identified “priority” areas within the Following Heiner et al. [2010] and Higgins (pers. ecoregion based on species richness and intact habi- comm.), we defined an analysis that would identify tat. However, we recognized that a terrestrial-based riverine conservation priority areas based on representation (species and habitat richness) and ecological condition (derived from Human Threats Index). If, in the future we choose to select a limited number of sites, we can incorporate additional criteria, con- nectivity and efficiency, to select the most opportu- nistic and effective areas to apply our resources.

Aquatic Ecosystem Classification The GAP project used a hierarchical classification to delineate the Missouri River Basin into nested levels (as described below and in Table 1). The Northern Great Plains (NGP) portion of the Mis- souri River Basin is contained in one Zone - Nearc- tic, one Subzone - Arctic/Atlantic, and one Region - Mississippi. Within the NGP, there are eight Aquatic Subregions (Figure 2), 22 Ecological Drainage Units (Figure 3), and 24 Aquatic Ecological System Types (Figure 4).

Figure 1. Missouri River Basin study area in comparison to the Northern Great Plains Ecoregion.

3 Table 1. Hierarchical framework for classifying the Missouri River Basin in the aquatic GAP project. Table from Sowa et al. [2007]. Defining Physical Defining Biological Level Description Features Features Six major zoogeographic zones of Continental boundaries Family-level patterns the world that resulted from distinct Global climate Endemism Zones evolutionary histories associated with plate tectonics Subcontinental zoogeographic strata Major river networks and Family-level patterns with relatively unique aquatic assem- basin boundaries Endemism Subzones blages created in large part by plate Regional climate tectonics, glaciation, and mountain building Subzone zoogeographic strata cre- Major river networks and Family- and species- ated in large part by drainage network basin boundaries level patterns patterns that determine dispersal Regional climate Endemism Regions routes and isolation mechanisms that Phylogenetics have resulted in different responses to long-term changes in climate Region stratification units. Large Regional climate Family- and species- areas of similar climate and physiog- Physiography level patterns raphy that often correspond to broad- General physiognomy of Endemism scale patterns in dominant vegetation vegetation Distinct foraging, repro- Aquatic Subregions ductive, and habitat-use guilds Distinct physiological tolerances Subregion zoogeographic strata. Ag- Drainage boundaries Family- and species- Ecological Drainage gregates of subdrainages with similar Physiography level patterns Units physiographic character and a com- Endemism mon evolutionary history. Phylogenetics Hydrogeomorphic subunits of Eco- Watershed boundaries Species-level patterns logical Drainage Units. Hydrologic Position within larger Distinct foraging, repro- units with similar physiographic drainage ductive, and habitat-use Aquatic Ecological character, basin morphometry, and Local and watershed guilds System Types position within the larger drainage. physiography Distinct physiological Represent ecological neighborhoods; Local climate tolerances each type contains similar combina- Basin morphometry tions of valley segment types. Hydrogeomorphic subunits of Aquatic Temperature Species-level patterns Ecological Systems. Aggregates of Stream size Distinct foraging, repro- stream reaches with broad similarities Permanence of flow ductive and habitat-use Valley Segment Types in fluvial processes, sediment trans- Position within drainage guilds port, riparian vegetation, and thermal network Distinct physiological regime. Valley geomorphology tolerances Hydrogeomorphic subunits of Valley Depth Species-level patterns Segment Types (e.g., riffle, pool, run). Velocity Distinct foraging, repro- Substrate ductive and habitat-use Habitat Unit Types Position within the chan- guilds nel Physical forming features

4 Figure 2. Aquatic subregions of the Northern Great Plains Ecoregion as delineated by Annis et al. [2010].

5 Figure 3. Ecological drainage units of the Northern Great Plains Ecoregion as delineated by Annis et al. [2010].

6 # Name 1 Jefferson River 2 Deep Creek 3 Belle Fourche River 4 Middle Yellowstone River 5 Sunlight Creek 6 Sun River 7 Clarks Fork Yellowstone River 8 Sage Creek 9 Horse Creek 10 Branch Knife River 11 Upper Republican River 12 Tongue River 13 Loup River 14 Rose Creek 15 Lower North Platte River 16 Laramie River 17 Smoky Hill River 18 Gooseberry Creek 19 West Plum Creek 20 Lower Musselshell River 21 Cannonball River 22 Lower Little White River 23 Missouri River 24 Choteau Creek

Figure 4. Aquatic ecological system types of the Northern Great Plains Ecoregion as delineated by Annis et al. [2010]. Note: Each Aquatic ecological system may have multiple polygons (shown in the same color), however only the largest unit of each type is numbered.

7 Fish Species Richness Following the procedure for calculating terrestrial species richness in the Ocean of Grass analysis [2012], we selected fish species from a combination of NatureServe G1-G3 listed species, endemic, keystone and focal species (as listed in Forrest et al. [2004] and TNC [1999]; focal species identified by senior-level WWF staff). A total of 16 species were identified (Table 2). We combined current distribution data (NatureServe 2010) for all species into one 1° grid of Species Richness (Figure 5). Distribution data was only available for the U.S. portion of the ecoregion, thus our current analysis is restricted to the United States. Table 2. List of species used to create Fish Species Richness layer. Common Name Scientific Name Lake sturgeon Acipenser fulvescens 7.5 Northern redbelly dace Chrosomus eos Brook stickleback Culaea inconstans Blue sucker Cycleptus elongates Iowa darter Etheostoma exile Figure 5. Fish Species Richness Index for the Northern Great Western silvery minnow Hybognathus argyritis Plains Ecoregion. Brassy minnow Hybognathus hankinsoni Plains minnow Hybognathus placitus Sturgeon chub Macrhybopsis gelida Sicklefin chub Macrhybopsis meeki Northern pearl dace Margariscus nachtriebi Hornyhead chub Nocomis biguttatus Fathead minnow Pimephales promelas Flathead chub Platygobio gracilis Paddlefish Polyodon spathula Pallid sturgeon Scaphirhynchus albus

Ecological Condition Index A Human Threats to Ecological Integrity Index was developed as part of the Missouri River Basin GAP project in an attempt to quantify relevant threats to aquatic systems (Table 3, Annis et al. 2010). We updated the layer with more recent data for Cropland,

Pasture, Impervious Surface, and Population Change 19.5 because of significant changes from the data used in the GAP analysis (Table 3). In our analysis, we used the threats index as a measure of ecological condition, i.e. the area with a low threat score likely had Figure 6. Ecological Condition Index for the Northern Great higher ecological integrity than area with high threat. Plains Ecoregion.

8 Within the entire Missouri River Basin, ecological condition ranged from 12 (good) to 32 (poor). In the Analysis NGP (updated index), ecological condition ranged We rescaled the Fish Species Richness Index and from 10 (good) to 29 (poor, Figure 6). Ecological Condition Index using linear interpolation Table 3. Components used to create the Human Threat Index to, respectively, 0 to 10 and -10 to 0 scales. These in the Missouri River Basin GAP project. Data in bold were were combined to create a Priority Riverine Area In- updated for this analysis to create an Ecological Condition dex (PRAI) that illustrates a scale from low quality Index. Table modified from Annis et al. [2010]. areas (low richness/poor condition) to high quality Threat Source areas (high richness/good condition, Figure 8). Various state and province Non-native Fish Species level agencies Following Heiner et al.[2011], we used Aquatic Eco- logical System (AES) types to address representation USGS (developed for Far- Impervious Surface gione et al. 2012 following of habitat types. AESs represent ecological “neigh- Yang et al. 2003) borhoods” in that they are fine-scale groupings of Cropland Data Layer stream units with similar ecological patterns and pro- Cropland (USDA 2012) cesses, thus they are a fitting unit to measure habi- USGS 2006 NLCD (MRLC; tat diversity (Annis et al. 2010, Heiner et al. 2011). Pasture Fry et al. 2001) We conducted a sensitivity analysis to explore the MoRAP (Created using Tiger interaction between the PRAI and the number of Road-Stream Crossings Road data and Mo Basin VST AES types (i.e. how many AES types are spatially streams) intersected with a given PRAI value, Figure 7). For example, with PRAI values of “≥7”, four AES types U.S. Census Data (2000 and Population Change 2010) are represented. Jenk’s natural breaks were used to identify a threshold PRAI value to distinguish Prior- MoRAP (Created using NHD Major Hydrologic ity Riverine Areas from other habitat. Lakes and Mo Basin VST Modification streams) U.S. Army Corps of Engi- Dams neers Results Coal Mines U.S. Bureau of Mines We found that a PRAI value of “≥-3” was necessary Lead Mines U.S. Bureau of Mines to include all AES types (Figure 7, yellow line). There Permitted Discharges EPA Envirofacts were two natural breaks (Figure 7, red dashed lines) Various state and province that could be used as thresholds for distinguishing Active Oil and Gas Wells level agencies Priority Riverine Areas, one between PRAI values of 25 2 and 3 and the other between 6 and 7. We chose to use the lower value to include as many AES types 20 that overlap with high quality habitat (high species # 15 richness/good condition) as possible. With a PRAI A value of “2” as a threshold, we identified 27,604,327 E 10 S acres of Priority Riverine Area within the U.S. por- 5 tion of the Northern Great Plains Ecoregion (Figure 9). Of this, 6,873,782 acres overlap with the Prior- 0 ity Habitat identified during the terrestrial analysis of -3 -1 1 3 5 7 9 PRAIPAAI Ocean of Grass [2012].

Figure 7. Sensitivity analysis showing interaction between Priority Riverine Area Index (PRAI) and Aquatic Ecological System (AES) types. At a PRAI value of -3 (yellow line), all 24 AES types in the Northern Great Plains Ecoregion are represented. The red dashed lines show Jenk’s natural breaks in the data between PRAI values of 2 and 3 and 6 and 7.

9 Figure 8. Priority Riverine Area Index of the Northern Great Plains Ecoregion. Higher values reflect high species richness/low threat and lower values reflect low species richness/high threat. Note: Species distribution data was not available for Canada, thus it was excluded from the index.

10 United States Census Bureau. http://www.census. References gov/# Annis, G. M., S. P. Sowa, D. D. Diamond, A. World Wildlife Fund-Northern Great Plains Garringer, P. Hanberry, and M. E. Morey. (2010). Program. (2012). NPCN Interactive Web Map. A GAP Analysis for Riverine Ecosystems of the http://www.npcn.net/npcnWebmap/index.html Missouri River Basin. Final Report, submitted to the USGS National Gap Analysis Program. 1,363 Yang L, Huang C, Homer C, Wylie B, Coan M. pp. (2003). An approach for mapping large-area impervious surfaces: synergistic use of Landsat Cropland Data Layer. USDA National Agriculture 7 ETM+ and high spatial resolution imagery. Statistics Service. http://www.nass.usda.gov/ Canadian Journal of Remote Sensing 29: 230– research/Cropland/SARS1a.htm 240. doi: 10.5589/m02-098 Fargione J, Kiesecker J, Slaats MJ, Olimb S. (2012). Wind and Wildlife in the Northern Great Plains: Identifying Low-Impact Areas for Wind Development. PLoS ONE 7(7): e41468. doi:10.1371/journal.pone.0041468 Forrest, S.C., Strand, H., Haskins, W.H., Freese, C., Proctor, J. & Dinerstein, E. (2004). Ocean of Grass: A Conservation Assessment for the Northern Great Plains. Northern Plains Conservation Network and Northern Great Plains Ecoregion, WWF-US, Bozeman, MT. Fry, J., Xian, G., Jin, S., Dewitz, J., Homer, C., Yang, L., Barnes, C., Herold, N., and Wickham, J., 2011. Completion of the 2006 National Land Cover Database for the Conterminous United States, PE&RS, Vol. 77(9):858-864. Heiner, M., Higgins, J., Li, X. and Baker, B. (2011). Identifying freshwater conservation priorities in the Upper Yangtze River Basin. Freshwater Biology, 56: 89–105. NatureServe. (2010). Digital Distribution Maps of the Freshwater Fishes in the Conterminous United States. Version 3.0. Arlington, VA. U.S.A. “Data provided by NatureServe.” Sowa, S.P., Annis, G., Morey, M.E. and D. D. Diamond. (2007). A Gap analysis and comprehensive conservation strategy for riverine ecosystems of Missouri. Ecological Monographs 77:301–334. The Nature Conservancy Northern Great Plains Recommended Citation: Steppe Ecoregional Conservation Team. (1999). Olimb, S.K. (2013). Northern Great Plains: Riverine Ecoregional Planning in the Northern Great Plains Analysis. Northern Great Plains Ecoregion, WWF- Steppe. US, Bozeman, MT.

11 Figure 9. Priority Riverine Area of the Northern Great Plains Ecoregion. Terrestrial Priority Area identified in a 2012 WWF analysis that considered species richness, intact habitat, and threats from oil/gas development and conversion to agriculture.

12 Appendix: Individual AES Types

Key

Focal Species Present: Focal species present Focal species not present

Prevalent Threats*: Threat is prevalent Threat is not prevalent

Map of featured Aquatic Ecological System (AES) type overlaying Priority Riverine area (PRA). When needed, yellow circles are used to draw attention to the area of AES/PRA overlap.

Information: Information about the featured AES type.

*Prevalence was determined by selecting the top two classes (i.e., the highest disturbance classes) of the expert-derived rankings developed by Annis et al. (2010) for each threat type. Threats listed “not prevalent” may exist within the AES, but are not having a substantial impact at this time.

13 Belle Fourche River AES

Priority Riverine Area

14 Belle Fourche River AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains, Yellowstone Mountains and Plains, Blue sucker Northern pearl dace Middle Missouri Plains Brassy Minnow Northern redbelly dace Ecological Drainage Unit(s): Bighorn, Cheyenne, Brook stickleback Paddlefish Musselshell, Powder/Tongue, Upper Missouri, Up- Fathead minnow Pallid sturgeon per Yellowstone Flathead chub Plains minnow Major Rivers/Streams*: Belle Fourche River, No- Hornyhead chub Sicklefin chub wood River and Smith River Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Landform Types*: Irregular Plains, Breaks and Low Hills Prevalent Threats: Soils*: Surface soils consist of silts to loams to clay Non-native fish species loam soils that generally exhibit moderate or very Cropland slow infiltration rates Pasture Geology*: Surficial geology is comprised of a com- Impervious surface bination of shaley or sandy ground, sandy and stony Road-Stream crossings colluviums, and floodplain and alluvium gravel ter- Permitted discharges races Population change Springs*: Total of 1,533 cold springs and one hot Major hydrologic modification/dams spring Oil & Gas Mean stream gradient*: Combined headwater and Coal mining creek mean stream gradient is 35.1 meters per kilo- Lead mining meter

Average July maximum temperature*: 28 de- grees Celsius

Average annual rainfall*: 34 - 54 centimeters per year

Total acres of AES: 1,964,292 acres

Acres of Priority Riverine Area: 820 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

15 Branch Knife River AES

Priority Riverine Area

16 Branch Knife River AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains, Yellowstone Mountains and Plains, Blue sucker Northern pearl dace Middle Missouri Plains Brassy Minnow Northern redbelly dace Ecological Drainage Unit(s): Big Muddy, Heart, Brook stickleback Paddlefish Little Missouri, Musselshell, Middle Missouri, Fathead minnow Pallid sturgeon Lower Yellowstone Flathead chub Plains minnow Major Rivers/Streams*: Knife River, Heart River Hornyhead chub Sicklefin chub and Big Dry Creek Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Landform Types*: Irregular Plains and Smooth Plains Prevalent Threats: Soils*: Surface soils consist of silts to loams that Non-native fish species generally exhibit moderate or very slow infiltration Cropland rates Pasture Geology*: Surficial geology is mostly comprised of Impervious surface thin and discontinuous ice-laid deposits with some Road-Stream crossings shaley or sandy ground Permitted discharges Springs*: Total of 383 cold springs Population change Major hydrologic modification/dams Mean stream gradient*: Combined headwater and Oil & Gas creek mean stream gradient is 10.8 meters per kilometer Coal mining Lead mining Average July maximum temperature*: 29 de- grees Celsius

Average annual rainfall*: 31 - 45 centimeters per year

Total acres of AES: 7,701,171 acres

Acres of Priority Riverine Area: 3,129,737 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

17 Cannonball River AES

Priority Riverine Area

18 Cannonball River AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains, Yellowstone Mountains and Plains, Mid- Blue sucker Northern pearl dace dle Missouri Plains, Platte Mountains and Plains Brassy Minnow Northern redbelly dace Ecological Drainage Unit(s): Cheyenne, Grand/ Brook stickleback Paddlefish Moreau, Heart, Little Missouri, Musselshell, Middle Fathead minnow Pallid sturgeon Missouri, Bad/Choteau, North Platte/South Platte, Flathead chub Plains minnow Lower Yellowstone Hornyhead chub Sicklefin chub Major Rivers/Streams*: Moreau, Cannonball Riv- Iowa darter Sturgeon chub er, Grand River and Heart River Lake sturgeon Western silvery minnow

Landform Types*: Smooth Plains, Irregular Plains, and Flat Plains Prevalent Threats: Non-native fish species Soils*: Surface soils consist of silts and loams to Cropland sandy loams that generally exhibit moderate or very Pasture slow infiltration rates Impervious surface Geology*: Surficial geology is mostly comprised of Road-Stream crossings shaley or sandy ground Permitted discharges Springs*: Total of 467 cold springs and two hot Population change springs Major hydrologic modification/dams Oil & Gas Mean stream gradient*: Combined headwater and creek mean stream gradient is 9.7 meters per kilo- Coal mining meter Lead mining

Average July maximum temperature*: 30 de- grees Celsius

Average annual rainfall*: 31 - 62 centimeters per year

Total acres of AES: 16,524,979 acres

Acres of Priority Riverine Area: 584,283 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

19 Choteau Creek AES

Priority Riverine Area

20 Choteau Creek AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains, Middle Missouri Plains, Northern Glaci- Blue sucker Northern pearl dace ated Plains Brassy Minnow Northern redbelly dace Ecological Drainage Unit(s): Big Muddy, Milk, Brook stickleback Paddlefish Middle Missouri, Bad/Choteau, Little Sioux/Nema- Fathead minnow Pallid sturgeon ha, James Flathead chub Plains minnow Major Rivers/Streams*: James River, Big Sioux Hornyhead chub Sicklefin chub River and Poplar River Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Landform Types*: Flat Plains

Soils*: Surface soils consist of silt and loam soils Prevalent Threats: that generally exhibit moderate infiltration rates Non-native fish species Geology*: Surficial geology is mostly comprised of Cropland ice-laid deposits that are mostly sand and silt Pasture Impervious surface Springs*: Total of 204 cold springs Road-Stream crossings Mean stream gradient*: Combined headwater and Permitted discharges creek mean stream gradient is 6.3 meters per kilo- Population change meter Major hydrologic modification/dams Average July maximum temperature*: 29 de- Oil & Gas grees Celsius Coal mining Lead mining Average annual rainfall*: 33 -73 centimeters per year

Total acres of AES: 17,779,037 acres

Acres of Priority Riverine Area: 3,958,290 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

21 Clarks Fork Yellowstone River AES

Priority Riverine Area

22 Clarks Fork Yellowstone River AES

Aquatic Subregion(s): Yellowstone Mountains and Focal Species Present: Plains, Middle Missouri Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Bighorn, Cheyenne, Brassy Minnow Northern redbelly dace Upper Missouri, Upper Yellowstone Brook stickleback Paddlefish Fathead minnow Pallid sturgeon Major Rivers/Streams*: South Platte River, Wind Flathead chub Plains minnow River and Bighorn River Hornyhead chub Sicklefin chub Landform Types*: No dominant landform types Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Soils*: Variety of soil textures that generally exhibit moderate to very slow infiltration rates Prevalent Threats: Geology*: Surficial geology is mostly comprised Non-native fish species of shaley or sandy ground, with a mixed of various other geology types Cropland Pasture Springs*: Total of 939 cold springs and 13 hot Impervious surface springs Road-Stream crossings Mean stream gradient*: Combined headwater and Permitted discharges creek mean stream gradient is 50.6 meters per kilo- Population change meter Major hydrologic modification/dams Average July maximum temperature*: 27 de- Oil & Gas grees Celsius Coal mining Lead mining Average annual rainfall*: 18 - 64 centimeters per year

Total acres of AES: 2,035,294 acres

Acres of Priority Riverine Area: 0 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

23 Deep Creek AES

Priority Riverine Area

24 Deep Creek AES

Soils*: Surface soils consist of silts to loams to Prevalent Threats: sandy loam soils that mostly exhibit moderate infil- Non-native fish species tration rates but also have some slow to very slow Cropland infiltration rates Pasture Geology*: Surficial geology is almost entirely com- Impervious surface prised of sandy and stony colluvium Road-Stream crossings Springs*: Total of 1,920 cold springs and 26 hot Permitted discharges springs Population change Major hydrologic modification/dams Mean stream gradient*: Combined headwater and Oil & Gas creek mean stream gradient is 53.4 meters per kilometer Coal mining Lead mining Average July maximum temperature*: 26 de- grees Celsius

Average annual rainfall*: 26 to 79 centimeters per year

Total acres of AES: 1,500,776 acres

Acres of Priority Riverine Area: 0 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

25 Gooseberry Creek AES

Priority Riverine Area

26 Gooseberry Creek AES

Soils*: Surface soils consist of sandy loam to silts Prevalent Threats: and loams that generally exhibit moderate or very Non-native fish species slow infiltration rates Cropland Geology*: Surficial geology is predominantly san- Pasture dy ground mostly on poor consolidated sandstone Impervious surface Road-Stream crossings Springs*: Total of 1,020 cold springs and nine hot springs Permitted discharges Population change Mean stream gradient*: Combined headwater and Major hydrologic modification/dams creek mean stream gradient is 20.3 meters per kilo- Oil & Gas meter Coal mining Average July maximum temperature*: 28 de- Lead mining grees Celsius

Average annual rainfall*: 20 - 55 centimeters per year

Total acres of AES: 4,580,925 acres

Acres of Priority Riverine Area: 555,517 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

27 Horse Creek AES

Priority Riverine Area

28 Horse Creek AES

Aquatic Subregion(s): Yellowstone Mountains and Focal Species Present: Plains, Middle Missouri Plains, Platte Mountains Blue sucker Northern pearl dace and Plains Brassy Minnow Northern redbelly dace Ecological Drainage Unit(s): Cheyenne, Powder/ Brook stickleback Paddlefish Tongue Fathead minnow Pallid sturgeon Flathead chub Plains minnow Major Rivers/Streams*: Cheyenne River and Lit- tle Powder River Hornyhead chub Sicklefin chub Iowa darter Sturgeon chub Landform Types*: Irregular Plains, Breaks and Lake sturgeon Western silvery minnow Smooth Plains

Soils*: Surface soils consist of silts to loam soils Prevalent Threats: that generally exhibit very slow infiltration rates Non-native fish species Geology*: Surficial geology is mostly comprised of Cropland shaley or sandy ground Pasture Impervious surface Springs*: Total of 96 cold springs Road-Stream crossings Mean stream gradient*: Combined headwater and Permitted discharges creek mean stream gradient is 13.4 meters per kilo- Population change meter Major hydrologic modification/dams Average July maximum temperature*: 31 de- Oil & Gas grees Celsius Coal mining Lead mining Average annual rainfall*: 32 - 39 centimeters per year

Total acres of AES: 1,877,854 acres

Acres of Priority Riverine Area: 1,211 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

29 Jefferson River AES

Priority Riverine Area

30 Jefferson River AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Upper Missouri Brassy Minnow Northern redbelly dace Brook stickleback Paddlefish Major Rivers/Streams*: Missouri River, Jefferson Fathead minnow Pallid sturgeon River and Beaverhead River Flathead chub Plains minnow Landform Types*: Hills, Low Hills, Flat Plains, Ir- Hornyhead chub Sicklefin chub regular Plains, and Breaks Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Soils*: Surface soils consist of silts to loams to sandy loam soils that generally exhibit moderate or very slow infiltration rates Prevalent Threats: Non-native fish species Geology*: Surficial geology is mostly comprised of fan gravels, which is unique compared to all other Cropland types, with some sandy and stony colluvium derived Pasture mostly from sandstone and shale Impervious surface Road-Stream crossings Springs*: Total of 539 cold springs and 8 hot springs Permitted discharges Population change Mean stream gradient*: Combined headwater and Major hydrologic modification/dams creek mean stream gradient is one of the largest in Oil & Gas the basin at 62.2 meters per kilometer Coal mining Average July maximum temperature*: 27 de- Lead mining grees Celsius

Average annual rainfall*: 25 to 50 centimeters per year

Total acres of AES: 197,806 acres

Acres of Priority Riverine Area: 225 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

31 Laramie River AES

Priority Riverine Area

32 Laramie River AES

Aquatic Subregion(s): Middle Missouri Plains, Focal Species Present: Platte Mountains and Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Cheyenne, North Brassy Minnow Northern redbelly dace Platte/South Platte, Upper Yellowstone Brook stickleback Paddlefish Fathead minnow Pallid sturgeon Major Rivers/Streams*: North Platte River, Lara- Flathead chub Plains minnow mie River and Medicine Bow River Hornyhead chub Sicklefin chub Landform Types*: Irregular Plains, Low Hills, Iowa darter Sturgeon chub Smooth Plains and Breaks Lake sturgeon Western silvery minnow Soils*: Surface soils consist of silts to loams to sandy loams that generally exhibit moderate or very Prevalent Threats: slow infiltration rates Non-native fish species Geology*: Surficial geology is mostly comprised of Cropland fan gravels with some bouldery and sandy colluvi- Pasture ums on granite rocks Impervious surface Road-Stream crossings Springs*: Total of 1,367 cold springs and five hot springs Permitted discharges Population change Mean stream gradient*: Combined headwater and Major hydrologic modification/dams creek mean stream gradient is 26.8 meters per kilo- Oil & Gas meter Coal mining Average July maximum temperature*: 28 de- Lead mining grees Celsius

Average annual rainfall*: 28 - 57 centimeters per year

Total acres of AES: 2,237,115 acres

Acres of Priority Riverine Area: 0 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

33 Loup River AES

Priority Riverine Area

34 Loup River AES

Aquatic Subregion(s): Sandhills and Plains Focal Species Present: Blue sucker Northern pearl dace Ecological Drainage Unit(s): Middle Platte Brassy Minnow Northern redbelly dace Major Rivers/Streams*: Elkhorn River and Loup Brook stickleback Paddlefish River Fathead minnow Pallid sturgeon Landform Types*: Flat Plains and Smooth Plains Flathead chub Plains minnow Hornyhead chub Sicklefin chub Soils*: Surface soils consist of sands, silts and loams Iowa darter Sturgeon chub that exhibit the highest infiltration rates of any AES Lake sturgeon Western silvery minnow type in the basin

Geology*: Surficial geology is mostly comprised of Prevalent Threats: floodplain and alluvium gravel terraces, and deeply Non-native fish species weathered loess Cropland Springs*: No springs Pasture Mean stream gradient*: Combined headwater and Impervious surface creek mean stream gradient is one of the lowest in Road-Stream crossings the basin at 7.4 meters per kilometer Permitted discharges Population change Average July maximum temperature*: 31 de- grees Celsius Major hydrologic modification/dams Oil & Gas Average annual rainfall*: 57 - 71 centimeters per Coal mining year Lead mining Total acres of AES: 7,256,789 acres

Acres of Priority Riverine Area: 354,994 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

35 Lower Little White River AES

Priority Riverine Area

36 Lower Little White River AES

Aquatic Subregion(s): Middle Missouri Plains Focal Species Present: Blue sucker Northern pearl dace Ecological Drainage Unit(s): Cheyenne, White Brassy Minnow Northern redbelly dace Major Rivers/Streams*: White River and Hat Brook stickleback Paddlefish Creek Fathead minnow Pallid sturgeon Landform Types*: Irregular Plains, Smooth Plains Flathead chub Plains minnow and Breaks Hornyhead chub Sicklefin chub Iowa darter Sturgeon chub Soils*: Surface soils consist of silts and loams to Lake sturgeon Western silvery minnow clays and silty clays that generally exhibit very slow or moderate infiltration rates Prevalent Threats: Geology*: Surficial geology is mostly comprised of Non-native fish species Pliocene-age and older stream deposits, and shaley or sandy ground Cropland Pasture Springs*: Total of 64 cold springs Impervious surface Mean stream gradient*: Combined headwater and Road-Stream crossings creek mean stream gradient is 13.9 meters per kilo- Permitted discharges meter Population change Average July maximum temperature*: 31 de- Major hydrologic modification/dams grees Celsius Oil & Gas Coal mining Average annual rainfall*: 37 - 54 centimeters per Lead mining year

Total acres of AES: 4,841,680 acres

Acres of Priority Riverine Area: 625,073 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

37 Lower Musselshell River AES

Priority Riverine Area

38 Lower Musselshell River AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains, Yellowstone Mountains and Plains, Blue sucker Northern pearl dace Middle Missouri Plains Brassy Minnow Northern redbelly dace Ecological Drainage Unit(s): Bighorn, Chey- Brook stickleback Paddlefish enne, Grand/Moreau, Little Missouri, Marias, Mus- Fathead minnow Pallid sturgeon selshell, Middle Missouri, Powder/Tongue, White, Flathead chub Plains minnow Lower Yellowstone, Upper Missouri, Upper Yel- Hornyhead chub Sicklefin chub lowstone Iowa darter Sturgeon chub Major Rivers/Streams*: Little Missouri River, Lake sturgeon Western silvery minnow Musselshell River, Cheyenne River and Belle Four- che River Prevalent Threats: Landform Types*: Irregular Plains, Smooth Plains Non-native fish species and Breaks Cropland Pasture Soils*: Surface soils consist of clay to silty clays and silts to loam soils that generally exhibit very Impervious surface slow or moderate infiltration rates Road-Stream crossings Permitted discharges Geology*: Surficial geology is mostly comprised of Population change shaley or sandy ground and floodplain and alluvium gravel terraces Major hydrologic modification/dams Oil & Gas Springs*: Total of 262 cold springs Coal mining Mean stream gradient*: Combined headwater and Lead mining creek mean stream gradient is 15.3 meters per kilometer

Average July maximum temperature*: 31 de- grees Celsius

Average annual rainfall*: 31 - 52 centimeters per year

Total acres of AES: 9,203,796 acres

Acres of Priority Riverine Area: 707,833 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

39 Lower North Platte River AES

Priority Riverine Area

40 Lower North Platte River AES

Aquatic Subregion(s): Platte Mountains and Focal Species Present: Plains, Sandhills and Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Republican/Big Brassy Minnow Northern redbelly dace Blue, Middle Platte, North Platte/South Platte Brook stickleback Paddlefish Fathead minnow Pallid sturgeon Major Rivers/Streams*: Platte River, North Platte Flathead chub Plains minnow River and South Platte River Hornyhead chub Sicklefin chub Landform Types*: Flat Plains and Smooth Plains Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Soils*: Surface soils consist of silts to loams to sandy loams that generally exhibit moderate infiltration rates Prevalent Threats: Non-native fish species Geology*: Surficial geology is mostly comprised of floodplain and alluvium gravel terraces Cropland Pasture Springs*: Total of 116 cold springs Impervious surface Mean stream gradient*: Combined headwater and Road-Stream crossings creek mean stream gradient is 8.8 meters per kilo- Permitted discharges meter Population change Average July maximum temperature*: 31 de- Major hydrologic modification/dams grees Celsius Oil & Gas Coal mining Average annual rainfall*: 34 - 76 centimeters per Lead mining year

Total acres of AES: 3,427,821 acres

Acres of Priority Riverine Area: 670,241 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

41 Middle Yellowstone River AES

Priority Riverine Area

42 Middle Yellowstone River AES

Aquatic Subregion(s): Yellowstone Mountains and Focal Species Present: Plains, Upper Missouri Mountains and Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Big Muddy, Big- Brassy Minnow Northern redbelly dace horn, Marias, Musselshell, Lower Yellowstone, Up- Brook stickleback Paddlefish per Missouri, Upper Yellowstone Fathead minnow Pallid sturgeon Flathead chub Plains minnow Major Rivers/Streams*: Missouri River, Yellow- stone River, Teton River, Wind River Hornyhead chub Sicklefin chub Iowa darter Sturgeon chub Landform Types*: Smooth Plains, Flat Plains, Ir- Lake sturgeon Western silvery minnow regular Plains, Breaks

Soils*: Silts to loams to clay loam soils that gener- Prevalent Threats: ally exhibit moderate or very slow infiltration rates Non-native fish species Geology*: Mostly comprised of floodplain and al- Cropland luvium gravel terraces, and shaley or sandy ground Pasture Impervious surface Springs*: Total of 1,195 cold springs and three hot Road-Stream crossings springs Permitted discharges Mean stream gradient*: Combined headwater and Population change creek mean stream gradient is 18.1 meters per kilo- Major hydrologic modification/dams meter Oil & Gas Average July maximum temperature*: 30 de- Coal mining grees Celsius Lead mining Average annual rainfall*: 17 - 51 centimeters per year

Total acres of AES: 10,838,218 acres

Acres of Priority Riverine Area: 4,159,675 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

43 Missouri River AES

Priority Riverine Area

44 Missouri River AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains, Yellowstone Mountains and Plains, Blue sucker Northern pearl dace Middle Missouri Plains Brassy Minnow Northern redbelly dace Ecological Drainage Unit(s): Big Muddy, Middle Brook stickleback Paddlefish Missouri, Bad/Choteau, Lower Yellowstone Fathead minnow Pallid sturgeon Flathead chub Plains minnow Major Rivers/Streams*: Missouri River Hornyhead chub Sicklefin chub Landform Types*: Flat Plains, Breaks, Irregular Iowa darter Sturgeon chub Plains and Smooth Plains Lake sturgeon Western silvery minnow Soils*: Surface soils consist of silts to loams and clays to silty clays that generally exhibit moderate Prevalent Threats: or very slow infiltration rates Non-native fish species Geology*: Surficial geology is mostly comprised of Cropland floodplain and alluvium gravel terraces Pasture Impervious surface Springs*: Total of 97 cold springs Road-Stream crossings Mean stream gradient*: Combined headwater and Permitted discharges creek mean stream gradient is 10.2 meters per kilo- Population change meter Major hydrologic modification/dams Average July maximum temperature*: Not cal- Oil & Gas culated Coal mining Lead mining Average annual rainfall*: 33 - 107 centimeters per year

Total acres of AES: 8,624,734 acres

Acres of Priority Riverine Area: 3,607,866 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

45 Rose Creek AES

Priority Riverine Area

46 Rose Creek AES

Aquatic Subregion(s): Sandhills and Plains Focal Species Present: Blue sucker Northern pearl dace Ecological Drainage Unit(s): Republican/Big Blue, Middle Platte Brassy Minnow Northern redbelly dace Brook stickleback Paddlefish Major Rivers/Streams*: Wood River, Little Blue Fathead minnow Pallid sturgeon River and Moreau River Flathead chub Plains minnow Landform Types*: Smooth Plains, Flat Plains, Hornyhead chub Sicklefin chub Breaks and Irregular Plains Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Soils*: Surface soils consist of silts and loams that generally exhibit moderate infiltration rates Prevalent Threats: Geology*: Surficial geology is mostly comprised of Non-native fish species deeply weathered loess, which is unique within the basin Cropland Pasture Springs*: Total of 17 cold springs Impervious surface Mean stream gradient*: Combined headwater and Road-Stream crossings creek mean stream gradient is 7.5 meters per kilo- Permitted discharges meter Population change Average July maximum temperature*: 32 de- Major hydrologic modification/dams grees Celsius Oil & Gas Coal mining Average annual rainfall*: 54 - 109 centimeters per Lead mining year

Total acres of AES: 164,356 acres

Acres of Priority Riverine Area: 1,262 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

47 Sage Creek AES

Priority Riverine Area

48 Sage Creek AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains, Middle Missouri Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Big Muddy, Marias, Brassy Minnow Northern redbelly dace Milk, Musselshell, Bad/Choteau, Brook stickleback Paddlefish Fathead minnow Pallid sturgeon Major Rivers/Streams*: Milk River, Marias River Flathead chub Plains minnow and Frenchman Creek Hornyhead chub Sicklefin chub Landform Types*: Flat Plains, Smooth Plains and Iowa darter Sturgeon chub Irregular Plains Lake sturgeon Western silvery minnow Soils*: Surface soils consist of clay loams to silts to loams that generally exhibit slow infiltration rates Prevalent Threats: Non-native fish species Geology*: Surficial geology is almost entirely comprised of Ice-laid deposits with mostly sand and silt Cropland Pasture Springs*: Total of 838 cold springs and two hot Impervious surface springs Road-Stream crossings Mean stream gradient*: Combined headwater and Permitted discharges creek mean stream gradient is 10.7 meters per kilo- Population change meter Major hydrologic modification/dams Average July maximum temperature*: 29 de- Oil & Gas grees Celsius Coal mining Lead mining Average annual rainfall*: 28 - 62 centimeters per year

Total acres of AES: 15,665,660 acres

Acres of Priority Riverine Area: 2,598,319 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

49 Smoky Hill River AES

Priority Riverine Area

50 Smoky Hill River AES

Aquatic Subregion(s): Middle Missouri Plains, Focal Species Present: Platte Mountains and Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Niobrara, North Brassy Minnow Northern redbelly dace Platte/South Platte, White Brook stickleback Paddlefish Fathead minnow Pallid sturgeon Major Rivers/Streams*: Republican River, Solo- Flathead chub Plains minnow mon River, Smoky Hill River and Lodgepole Creek Hornyhead chub Sicklefin chub Landform Types*: Flat Plains and Smooth Plains Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Soils*: Surface soils consist of silts to loams that generally exhibit moderate infiltration rates Prevalent Threats: Geology*: Surficial geology is mostly comprised of Non-native fish species Pliocene-age and older stream deposits and floodplain and alluvium terraces Cropland Pasture Springs*: Total of 296 cold springs Impervious surface Mean stream gradient*: Combined headwater and Road-Stream crossings creek mean stream gradient is 9.1 meters per kilo- Permitted discharges meter Population change Average July maximum temperature*: 33 de- Major hydrologic modification/dams grees Celsius Oil & Gas Coal mining Average annual rainfall*: 36 - 73 centimeters per Lead mining year

Total acres of AES: 279,936 acres

Acres of Priority Riverine Area: 105,614 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

51 Sun River AES

Priority Riverine Area

52 Sun River AES

Aquatic Subregion(s): Upper Missouri Mountains Focal Species Present: and Plains, Yellowstone Mountains and Plains, Blue sucker Northern pearl dace Ecological Drainage Unit(s): Marias, Milk, Upper Brassy Minnow Northern redbelly dace Missouri, Upper Yellowstone Brook stickleback Paddlefish Fathead minnow Pallid sturgeon Major Rivers/Streams*: Sun River and Milk River Flathead chub Plains minnow Landform Types*: Varied and no single type has Hornyhead chub Sicklefin chub dominance Iowa darter Sturgeon chub Lake sturgeon Western silvery minnow Soils*: Surface soils consist of silts to loams, or clay loam soils that generally exhibit moderate or slow infiltration rates Prevalent Threats: Non-native fish species Geology*: Surficial geology is mostly comprised of shaley or sandy ground, and floodplain and al- Cropland luvium gravel terraces Pasture Impervious surface Springs*: Total of 196 cold springs and two hot Road-Stream crossings springs Permitted discharges Mean stream gradient*: Combined headwater and Population change creek mean stream gradient is 64 meters per kilo- Major hydrologic modification/dams meter Oil & Gas Average July maximum temperature*: 25 de- Coal mining grees Celsius Lead mining Average annual rainfall*: 30 - 85 centimeters per year

Total acres of AES: 1,480,938 acres

Acres of Priority Riverine Area: 690 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

53 Sunlight Creek AES

Priority Riverine Area

54 Sunlight Creek AES

Aquatic Subregion(s): Yellowstone Mountains and Focal Species Present: Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Upper Yellowstone Brassy Minnow Northern redbelly dace Brook stickleback Paddlefish Major Rivers/Streams*: Yellowstone River, Gall- Fathead minnow Pallid sturgeon atin River and Big Hole River Flathead chub Plains minnow Landform Types*: Low Mountains and Hills Hornyhead chub Sicklefin chub Iowa darter Sturgeon chub Soils*: Surface soils consist of silts to loams that Lake sturgeon Western silvery minnow generally exhibit moderate or very slow infiltration rates Prevalent Threats: Geology*: Surficial geology is mostly comprised of Non-native fish species deposits of mountain glaciers, with smaller amounts of other geology types Cropland Pasture Springs*: Total of 701 cold springs and 13 hot Impervious surface springs Road-Stream crossings Mean stream gradient*: Combined headwater and Permitted discharges creek mean stream gradient is 85.9 meters per kilo- Population change meter Major hydrologic modification/dams Average July maximum temperature*: 23 de- Oil & Gas grees Celsius Coal mining Lead mining Average annual rainfall*: 33 - 106 centimeters per year

Total acres of AES: 260,920 acres

Acres of Priority Riverine Area: 0 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

55 Tongue River AES

Priority Riverine Area

56 Tongue River AES

Landform Types*: Irregular Plains, Breaks, Smooth Plains and Low Hills Prevalent Threats: Non-native fish species Soils*: Surface soils consist of silts to loam soils Cropland that generally exhibit moderate to very slow infiltra- Pasture tion rates Impervious surface Geology*: Surficial geology is mostly comprised of Road-Stream crossings shaley or sandy ground Permitted discharges Springs*: Total of 3,185 cold springs and three hot Population change springs Major hydrologic modification/dams Oil & Gas Mean stream gradient*: Combined headwater and creek mean stream gradient is 22.2 meters per kilo- Coal mining meter Lead mining

Average July maximum temperature*: 29 de- grees Celsius

Average annual rainfall*: 27 - 59 centimeters per year

Total acres of AES: 17,273,840 acres

Acres of Priority Riverine Area: 2,901,743 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

57 Upper Republican River AES

Priority Riverine Area

58 Upper Republican River AES

Aquatic Subregion(s): Middle Missouri Plains, Focal Species Present: Sandhills and Plains, South Central Plains Blue sucker Northern pearl dace Ecological Drainage Unit(s): Cheyenne, Republi- Brassy Minnow Northern redbelly dace can/Big Blue, Niobrara, White Brook stickleback Paddlefish Fathead minnow Pallid sturgeon Major Rivers/Streams*: Republican River, Elk- Flathead chub Plains minnow horn River and Niobrara River Hornyhead chub Sicklefin chub Landform Types*: Two main landform types are Iowa darter Sturgeon chub Flat Plains and Smooth Plains Lake sturgeon Western silvery minnow Soils*: Surface soils consist of silts and loams to sands that generally exhibit moderate to high infil- Prevalent Threats: tration rates Non-native fish species Geology*: Surficial geology is mostly comprised of Cropland Pliocene-age and older stream deposits, floodplain Pasture and alluvium gravel terraces, and sand sheets Impervious surface Road-Stream crossings Springs*: Total of 196 cold springs Permitted discharges Mean stream gradient*: Combined headwater and Population change creek mean stream gradient is 11.9 meters per kilo- Major hydrologic modification/dams meter Oil & Gas Average July maximum temperature*: 31 de- Coal mining grees Celsius Lead mining Average annual rainfall*: 35 - 79 centimeters per year

Total acres of AES: 7,563,956 acres

Acres of Priority Riverine Area: 1,617,234 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.

59 West Plum Creek AES

Priority Riverine Area

60 West Plum Creek AES

Landform Types*: Smooth Plains, Irregular Plains and Breaks Prevalent Threats: Non-native fish species Soils*: Surface soils consist of clay to silty clay Cropland soils that generally exhibit the slowest infiltration Pasture rates in the basin Impervious surface Geology*: Surficial geology mostly consists of Road-Stream crossings shaley or sandy ground on mixed sandstone and Permitted discharges shale formations with considerable swelling clay Population change Springs*: Total of 183 cold springs Major hydrologic modification/dams Oil & Gas Mean stream gradient*: Combined headwater and creek mean stream gradient is 11.3 meters per kilo- Coal mining meter Lead mining

Average July maximum temperature*: 31 de- grees Celsius

Average annual rainfall*: 30 - 54 centimeters per year

Total acres of AES: 10,387,330 acres

Acres of Priority Riverine Area: 2,011,077 acres

*Data from Annis et al. (2010). Information reflects all AES types within the entire Missouri River Basin, not the Northern Great Plains subset.