Ecological site group description

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

Climate

MLRA 54 is considered to have a continental climate - cold winters and hot summers, low humidity, light rainfall, and much sunshine. Extremes in temperature are characteristic. The climate is the result of this MLRA's location in the geographic center of North America. There are few natural barriers on the northern Great Plains. The air masses move unobstructed across the plains and account for rapid changes in temperature. \nAnnual precipitation ranges from 14 to 18 inches per year. The normal average annual temperature is about 42 degrees F. January is the coldest month with average temperatures ranging from about 13 degrees F (Beach, ND) to about 72 degrees F (Timber lake, SD). The range of normal average monthly temperatures between the coldest and warmest months is about 57 degrees F. This large annual range attests to the continental nature of this MLRA's climate. Hourly winds are estimated to average about 11 miles per hour annually, ranging from about 13 miles per hour during the spring to about 10 miles per hour during the summer. Daytime winds are generally stronger than nighttime and occasional strong storms may bring brief periods of high winds with gusts to more than 50 miles per hour.\nGrowth of native cool-season plants begins in late March and continues to early to mid-July. Native warm-season plants begin growth in mid-May and continue to the end of August. Green up of cool-season plants can occur in September and October when adequate soil moisture is present.\nThis site occurs within the Knife River Watershed, located in the Missouri Plateau portion of the Northwestern Great Plains Region of North Dakota (Severson and Sieg 2006). The landscape of the Unglaciated Plains is classified as a semiarid rolling plain of shale and sandstone with areas of buttes and badlands. The Missouri Plateau, which is located to the west of the Missouri River, this region was not impacted by glaciation and as a result retained its original soils and hydrologic patterns. The valleys of the streams in MLRA 54 were developed by down-cutting of the prehistoric Missouri River system through the soft sandstone and shale that make up the Fort Union Formation that is comprised of a group of Paleocene Epoch formations including: Sentinel Butte, Bullion Creek, Slope, Cannonball, and Ludlow (Bluemle and Biek 2007). The surrounding landscape is comprised of highly erodible sediments overlaid by a protective layer of sandstone and/or limestone. Erosion of sedimentary material over time has resulted in the entrenchment of streams and the formations of multiple terraces. The floodplain is composed primarily of sands with silts and clays present in the banks.\nThe soils that have developed on the floodplains of Spring Creek and Knife River are derived from material of a similar geological formation. Both of the streams cut through the Sentinel Butte Formation, with minor amounts of sediment coming from higher elevations that contain White River Group, Golden Valley Formation, and glaciated materials.\nThe two sites are different in how the soils have developed. The developmental differences of these soils indicates the amount and how the sediments are eroded or deposited depending on where you are at in the watershed. At the beginning of the watershed in the case of the Spring creek site, the sediment load isn't as great and does not bury the existing soil surface beyond the bankflow area. This allows for a more stable landform and increased vegetation which is needed in the development of the Mollisols soil order. The Knife River has a greater sediment load and will deposit more sediments as the water flow slows. The sediments that are deposited will bury the existing soil surface. When this occurs, there is not enough time for the soil to develop and lack of vegetation to improve the soil, so the Entisols soil order occurs; which is the first soil order in the soil development process.\nThe soils on the floodplain landform (bankflow) are Aquents. The Spring creek site is a Typic Psammaquent and the Knife River site is a Typic Fluvaquent. The soils have developed from different particle-sizes, but otherwise the soils are similar in how water is influencing the soil. These two soils will occur on this landform anywhere along the two stream systems. After the first landform, the soils of the two sites are different. The soils at the Spring creek site have developed into Mollisols. The soils are as follows: floodplain step classified as a Fluventic Endoaquoll; the low terrace also classified as a Fluventic Endoaquoll, but if the upland water flow had not occured at this site that caused an elevated water table, it wold have classified as a Fluventic Haplustoll; the high terrace classified as a Fluventic Haplustoll. The soils at the Knife River site are as follows: the soil on the floodplain step classified as an Aeric Fluvaquent; the low terrace was not investigated, but form observation and tacit knowledge of the soils that occur at these positions, the soil would classify similar to an Oxyaquic Ustifluvent; the high terrace classified as a Fluventic Haplustoll, which is similar to the Spring Creek site, except the soil textures were different.\nThe salinity that is recorded was from field observations at the sites. There was very little salinity observed in the soils at both sites, so the values recorded are from none to slight salinity. At the Spring Creek site, there are areas that were downstream that appeared to have moderate salinity and at the Knife River site, slight salinity was noticed along the stream edge.

Vegetation dynamics

MLRA 54 is considered to have a continental climate - cold winters and hot summers, low humidity, light rainfall, and much sunshine. Extremes in temperature are characteristic. The climate is the result of this MLRA's location in the geographic center of North America. There are few natural barriers on the northern Great Plains. The air masses move unobstructed across the plains and account for rapid changes in temperature. \nAnnual precipitation ranges from 14 to 18 inches per year. The normal average annual temperature is about 42 degrees F. January is the coldest month with average temperatures ranging from about 13 degrees F (Beach, ND) to about 72 degrees F (Timber lake, SD). The range of normal average monthly temperatures between the coldest and warmest months is about 57 degrees F. This large annual range attests to the continental nature of this MLRA's climate. Hourly winds are estimated to average about 11 miles per hour annually, ranging from about 13 miles per hour during the spring to about 10 miles per hour during the summer. Daytime winds are generally stronger than nighttime and occasional strong storms may bring brief periods of high winds with gusts to more than 50 miles per hour.\nGrowth of native cool-season plants begins in late March and continues to early to mid-July. Native warm-season plants begin growth in mid-May and continue to the end of August. Green up of cool-season plants can occur in September and October when adequate soil moisture is present.\nThis site occurs within the Knife River Watershed, located in the Missouri Plateau portion of the Northwestern Great Plains Region of North Dakota (Severson and Sieg 2006). The landscape of the Unglaciated Plains is classified as a semiarid rolling plain of shale and sandstone with areas of buttes and badlands. The Missouri Plateau, which is located to the west of the Missouri River, this region was not impacted by glaciation and as a result retained its original soils and hydrologic patterns. The valleys of the streams in MLRA 54 were developed by down-cutting of the prehistoric Missouri River system through the soft sandstone and shale that make up the Fort Union Formation that is comprised of a group of Paleocene Epoch formations including: Sentinel Butte, Bullion Creek, Slope, Cannonball, and Ludlow (Bluemle and Biek 2007). The surrounding landscape is comprised of highly erodible sediments overlaid by a protective layer of sandstone and/or limestone. Erosion of sedimentary material over time has resulted in the entrenchment of streams and the formations of multiple terraces. The floodplain is composed primarily of sands with silts and clays present in the banks.\nThe soils that have developed on the floodplains of Spring Creek and Knife River are derived from material of a similar geological formation. Both of the streams cut through the Sentinel Butte Formation, with minor amounts of sediment coming from higher elevations that contain White River Group, Golden Valley Formation, and glaciated materials.\nThe two sites are different in how the soils have developed. The developmental differences of these soils indicates the amount and how the sediments are eroded or deposited depending on where you are at in the watershed. At the beginning of the watershed in the case of the Spring creek site, the sediment load isn't as great and does not bury the existing soil surface beyond the bankflow area. This allows for a more stable landform and increased vegetation which is needed in the development of the Mollisols soil order. The Knife River has a greater sediment load and will deposit more sediments as the water flow slows. The sediments that are deposited will bury the existing soil surface. When this occurs, there is not enough time for the soil to develop and lack of vegetation to improve the soil, so the Entisols soil order occurs; which is the first soil order in the soil development process.\nThe soils on the floodplain landform (bankflow) are Aquents. The Spring creek site is a Typic Psammaquent and the Knife River site is a Typic Fluvaquent. The soils have developed from different particle-sizes, but otherwise the soils are similar in how water is influencing the soil. These two soils will occur on this landform anywhere along the two stream systems. After the first landform, the soils of the two sites are different. The soils at the Spring creek site have developed into Mollisols. The soils are as follows: floodplain step classified as a Fluventic Endoaquoll; the low terrace also classified as a Fluventic Endoaquoll, but if the upland water flow had not occured at this site that caused an elevated water table, it wold have classified as a Fluventic Haplustoll; the high terrace classified as a Fluventic Haplustoll. The soils at the Knife River site are as follows: the soil on the floodplain step classified as an Aeric Fluvaquent; the low terrace was not investigated, but form observation and tacit knowledge of the soils that occur at these positions, the soil would classify similar to an Oxyaquic Ustifluvent; the high terrace classified as a Fluventic Haplustoll, which is similar to the Spring Creek site, except the soil textures were different.\nThe salinity that is recorded was from field observations at the sites. There was very little salinity observed in the soils at both sites, so the values recorded are from none to slight salinity. At the Spring Creek site, there are areas that were downstream that appeared to have moderate salinity and at the Knife River site, slight salinity was noticed along the stream edge.

Major Land Resource Area

MLRA 054X
Rolling Soft Shale Plain

Stage

Provisional

Contributors

Curtis Talbot