U.S. DEPARTMENT OF THE INTERIOR Prepared in cooperation with the SCIENTIFIC INVESTIGATIONS REPORT 2014−5223 U.S. GEOLOGICAL SURVEY UNIVERSITY OF , and the Geomorphic surfaces—PLATE 1 U.S. FISH AND WILDLIFE SERVICE O'Connor, J.E., McDowell, P.F., Lind, Pollyanna, Rasmussen, C.G., Keith, M.K., 2015, Geomorphology and Flood-Plain Vegetation of the Sprague and Lower Sycan Rivers, , Oregon

DESCRIPTION OF MAPPING UNIT

Geomorphic Flood Plain (Holocene)—Area of Holocene channel migration; channels and active flood plains along the North Fork Active Tributary Flood Plain (Holocene)—Tributary channel, flood plain, and basin fill deposits in low-gradient areas subject to Sycan Flood Deposits (Holocene)—A prominent planar surface extending south discontinuously from the lower Sycan River Qfp Sprague, South Fork Sprague, main-stem Sprague, and Sycan Rivers. This map unit, divided into valley segments, is the area of Qtfp inundation, and unconfined by valley margins. Tributary channels and flanking surfaces grade to modern main-stem channels Qsf canyon to its confluence with the . This surface stands 3 m above the active flood plain at the downstream end of the detailed mapping analysis of constructed features, historical channel change, and vegetation described in this report. This and flood plains, forming narrow and elongate map units extending into the uplands where channels become increasingly Sycan Canyon, and descends to flood plain level near the Sycan River confluence with the Sprague River. It is underlain by as Portland unit encompasses the area of channels, abandoned channels, and bar-and-scroll topography evident on the 2004 Light topographically confined. In some reaches, especially the Kamkaun Spring, the tributary valleys have very low, nearly much as 3.35 m of bedded sand and gravel composed almost entirely of Mazama pumice. The deposits fine and thin Detection and Ranging (lidar) topographic data. The presence of main-stem channel topographic features distinguishes this horizontal, gradients, whereas in many locations, tributary valley flood plains have gradients approaching 5 degrees. The downstream, where they are overlain by alternating beds of silty fine sand and sand. At their apex near the downstream end of EXPLANATION unit from the main-stem valley fill unit. Soils are typically poorly drained and include volcanic-ash-rich Mollisols dominated by distinction with tributary fans and colluvium is primarily on the basis of plan-view morphology and slope but is locally indistinct. the Sycan Canyon, these deposits grade to surfaces mantled with 1-m-diameter rounded basalt boulders, apparently derived 6/28/07-2 the Klamath-Ontko-Dilman series (Cahoon, 1985). Stratigraphy exposed on eroding streambanks and from augering show that Primary soils on tributary flood plains are Inceptisols and Mollisols, which typically form in late Pleistocene or Holocene from the canyon rim and walls and transported downstream. The soil capping these surfaces is mainly classified as an Ashy Water—Located outside mapped area. From National Stratigraphy site—With site number(s). See these flood-plain deposits almost everywhere formed after the 7,700 cal yr BP (calendar years before present) Mazama deposits (Cahoon, 1985). Typic Cryopsamment, indicating poorly developed soils formed in sandy parent materials. The pumiceous sand and gravel Hydrography Dataset figures 4, 5, 8, and 9 to view stratigraphic section eruption. In places, particularly along the lower Sycan River (Lind, 2009) and the North Fork Sprague River, stratigraphic overlies organic-rich silt and clay deposits, locally peaty, and commonly containing within 10 centimeters (cm) of its top, a OREGON relations show at least two episodes of flood-plain erosion and rebuilding in the last 7,700 cal yr BP. The geomorphic flood plain 0.5-to-2.5-cm-thick layer of silt- and sand-size Mazama tephra. This fallout tephra, constrained by radiocarbon dates here and Primary channel—Mapped from 2000 aerial photographs DAM Former dam site has formed in the last 7,700 cal yr BP from a combination of channel migration, channel avulsion, and lateral and vertical Active Tributary Fans (Quaternary)—Shallowly sloping (less than 10 degrees) alluvial transport surfaces grading to modern in other areas, resulted from the Mazama eruption of about 7,700 cal yr BP. The inference is that this terrace resulted from a Contact accretion of bedload and suspended load deposits. The geomorphic flood plain is mapped on the basis of morphology and does Qtf main-stem and tributary flood plains, commonly with a singular or composite fan-shaped down-gradient terminus. These are large, pumice-laden flood down the Sycan River within a few decades or centuries of the 7,700 cal yr BP Mazama eruption. A McCready not necessarily correspond to a specific height above the channel or areas subject to flooding at a specific frequency. Locally active alluvial transport surfaces heading from confined tributaries, colluvial slopes and bedrock, and have formed where flow plausible source for such a flood was temporary impoundment of a lake in the Sycan Marsh area, possibly by dunes of Mazama 35 Flood-plain transects—Spaced every 1 kilometer, labeled Spring Spring includes springs and associated wetland deposits within the area of Holocene channel migration. routes expand onto flat terraces, flood plains, and other flat bottomland surfaces. These surfaces are commonly gradational pumice blocking the Sycan River channel near the marsh outlet (Lind, 2009). The Sycan flood deposits are coarse, loose, and every 5 kilometers starting from mouth of river or tributary Sprague River Study with colluvial slopes and valley bottomlands, but with intermediate slopes. Active fan surfaces are mantled with Haploxerolls, erode readily from disturbed sites, particularly along tall banks flanking the modern channel or flood plain. 11501000 Streamflow-gaging station area Basin Cryorthents, Cryofluvents, Cryoborolls, and Cryaquepts soil taxonomic classes, all of which have only incipient horizon Sprague River Basin boundary Main-Stem Valley Fill (Holocene)—Flood plain and basin areas outside of active channel areas of the geomorphic flood plain, but development in the form of translocated and accumulated carbonates and silica, consistent with late Pleistocene to Holocene U.S. Geological Survey Qmvf historically are subject to overbank flooding. Low-gradient planar surfaces totaling 28 km2 (square kilometers) occupy broad Streams—From National Hydrography Dataset. Not Klamath Falls ages. Many active fans have surfaces post-dating the 7,700 cal yr BP Mazama eruption. Active fans episodically provide Pond and Wetland Deposits (Holocene)—Lacustrine deposits associated with modern or historical waterbodies; only shown Oregon Water Resources Department areas flanking the Sprague River corridor, particularly in the Kamkaun Spring, S'Ocholis Canyon, and Buttes of the Gods valley Qw displayed within geomorphic flood plain sediment to the main-stem rivers and flood plains. outside of the geomorphic flood plain. Several small closed depressions host seasonal to perennial waterbodies. Most are segments. Additionally, this map unit includes bottomlands flanking the post-Mazama (7,700 cal yr BP) zone of channel within areas of valley fill or occupy depressions within abandoned fans. Nearly all are used for water storage with dikes or small migration (the geomorphic flood plain) in the Council Butte and Beatty-Sycan valley segments. The surfaces generally have Road dams augmenting storage capacity. soils mapped as Inceptisols or Mollisols formed in part by cumulic deposition of silt and clay during overbank flooding. Many of Abandoned Fan (Quaternary/Tertiary)—Incised tributary fan deposits, surfaces as much as 30 m above active channels. These Major (highway) the surfaces are flooded during periods of high water, but show no evidence of hosting major channels. Many of these surfaces Qfu shallowly sloping (less than 10 degrees) alluvial transport surfaces have been incised because of base-level fall. Large Minor are now diked and drained. Some of these broad valley bottoms marginal to the main river course, especially within the abandoned fan complexes border the southern Sprague River valley in the Buttes of the Gods and Council Butte valley Colluvial Slopes (Quaternary)—Hillslope colluvium and piedmont slope deposits. Steep but smooth slopes, as much as about 35 Kamkaun Spring, S'Ocholis Canyon, and Buttes of the Gods valley segments, seem to be long-term sediment depocenters 121°40’ Qf segments. Constriction of the valley by one such fan near the settlement of Sprague River separates these two valley segments. Qc degrees, underlain by unconsolidated regolith and formed by gravitational and alluvial transport processes such as rockfall, because of overall Sprague River valley aggradation, perhaps in conjunction with block faulting along the north-northwest 1 Locally, abandoned fan surfaces are enumerated 1 through 4 on the basis of increasing degree of incision (and presumably avalanching, biogenic disturbance, and sheet wash transport. Colluvial slopes typically head at steep bedrock outcrops, which trending faults transecting the lower part of the Sprague River Valley. Within the Council Butte and Beatty-Sycan valley Qf age). The older surfaces have only isolated remnants of original transport surfaces, underlain by fluvial gravel, separated by are the source of material, and transition downslope to alluvial transport surfaces. Colluvium is locally an important source of segments, the valley fill unit encompasses broad tracts of seasonally inundated lowlands flanking the Sprague River, but is 2 younger (and lower) fan and tributary surfaces and by slopes formed in the underlying Tertiary lacustrine sediment. Some coarse (gravel-size) material to the Sprague and Sycan Rivers, especially in canyon segments where much of the flood plain is outside areas occupied by late Holocene channels. In places, this unit may correspond with low terraces mapped in the Council Qf abandoned fan surfaces, including those south of the Sprague River Valley near Beatty and Bly, are partly formed of pumiceous bordered by colluvium or bedrock. The distinction of colluvial slopes and active tributary fans is locally arbitrary, but tributary Buttes and Beatty Gap valley segments. 3 pyroclastic flow deposits derived from Tertiary volcanic centers to the south (Sherrod and Pickthorn, 1992). Near the Sprague fan slopes typically are less than 10 degrees. and Sycan Rivers, these tributary fan deposits are locally interbedded with main-stem fluvial channel and overbank deposits. Qf4 Terrace (Quaternary)—Terrace deposits along main-stem Sprague River. Planar alluvial surfaces as much as 50 meters (m) Primary soil taxonomic classes on abandoned fan surfaces include Haploxerolls, Argixerolls, and Durixerolls, indicating minor Qtu above the active flood plain flank the Sprague River near its confluence with the Williamson River. Similarly, terraces at to significant accumulations of clays, silica, and carbonate. The ages of these surfaces likely range from Pliocene to possibly Landslide Deposits (Quaternary)—Deposits of large mass movements, primarily rotational failures, usually with steep hummocky several elevations ranging as much as 20 m above the geomorphic flood plain border the Sprague River in the Chiloquin as young as early Holocene. All abandoned fan deposits, however, likely post-date the approximately 3.0 million year old Basalt Qls topography bounded on upslope margins by arcuate scarps. A few landslides are evident in the Chiloquin Canyon valley Qt1 Canyon, Braymill, Kamkaun Spring, S'Ocholis Canyon, and Buttes of the Gods valley segments. Locally, terraces are enumer- D of Knot Tableland. The abandoned fans are largely stable features that contribute little sediment directly to the modern fluvial segment and in the lowermost part of the Sycan River canyon within the Coyote Bucket valley segment. The Sycan River canyon A ated 1 through 4 on the basis of increasing elevation (and presumably age) above the geomorphic flood plain. Isolated low Qtf W O system. These abandoned alluvial fans reflect overall Tertiary and Quaternary valley incision of the Sprague River valley, 121°50’ Qls ILL R landslides likely blocked the channel, and the affected reaches traverse accumulations of large blocks of volcanic rock from IAM Qt terraces flank the Sprague River in the Council Butte and Beatty Gap segments, as well as along the lower Sycan River. The Qtf SO ER 2 probably in conjunction with integration and incision of the Sprague River through fault-uplifted canyon segments downstream. the canyon rim. N RIV Hawks terrace surfaces are underlain by fluvial gravel and are generally stable features upon which Haploxeroll soils have formed, Qmvf Whitehorse Qtf Lake Qt indicating formation of a cambic B horizon and some carbonate accumulation (Cahoon, 1985). Terrace risers locally expose Qmvf Qt 3 Qmvf Springs 1 Tertiary lacustrine sediment or other bedrock units, indicating that at least some of the terraces are strath surfaces cut into Qtf e Undifferentiated Bedrock (Tertiary)—Irregular, typically hummocky or steep topography, underlain by Tertiary lacustrine sediment Qtf u Qfp 6/28/07-2 the soft Tertiary sediment. The positions and degree of soil development are consistent with ages of late Tertiary through Active Springs and Spring Deposits (Holocene)—Active springs and associated wetland deposits. Six areas of springs and Qt1 g R Qt4 Tbr Qt a iv Qsw or volcanic rocks. This unit was mapped only where completely surrounded by mapped alluvial or colluvial surfaces. 1 r er Quaternary. Many or all of these terraces pre-date the 7,700 cal yr BP Mazama eruption, judging from the presence of Mazama related features such as ponds, wetlands, and channels are within the map area but outside the geomorphic flood plain. Most Braymill p 25 Qtfp Tbr Qt2 Qt S fallout tephra in the upper parts of their soil profiles (Cahoon, 1985). Like the abandoned alluvial fans, the terraces result from are contiguous with the geomorphic flood plain or flanking terraces. Spring outlets with flowing water have sandy to gravel 1 Qmvf Lalo Qc Qt Qt1 episodic filling and incision during Quaternary downcutting of the Sprague River. Some of this downcutting may have resulted substrates, surrounding areas consisting mostly of saturated peat deposits formed from aquatic vegetation. Most spring Qt2 Springs 2 Tbr from broadscale base-level fall associated with integration of the upper basin (Sherrod and Pickthorn, 1992), Qt1 15 Qt complexes are connected to the Sprague and Sycan Rivers by sand-bed spring channels. 1 Qt Qt Qt 3 but some terrace sequences may reflect more local tectonic blockages associated with the north-northwest trending Qls 1 1 Tbr Kamkaun Cave Mountain 20 Spring basin-and-range faulting affecting the western Sprague River valley segments. Qt Qt 3 1 30 10 Qtfp Qt Qc 9/20/06-4, 5 McCready Qtf 1 Qls Springs 11501000 Qc SPRAGUE RIVER ROAD 9/15/06-2 Qfp 42°35’ Qtfp Qmvf Qt1 42°35’ Qt Qtu 9/20/06-1,2, 3 2 9/15/06-1a, b 121°20’ Qt4 Qt 1 Tbr Qmvf Chiloquin Qt LO 2 NE P Qtfp Qc 0 I Qt1 Qt3 N Tbr E R Qt 35 O 2 Qfp A Qt2 Qt1 Qtfp Tbr Qc Qc D

Qt4 Qc Qtf

r

e Qtu 5

S

v Qt Qtfp i 3 Qt1 y

c

R C S’Ocholis Qt Canyon 1

Qt a Qls Qtf FORMER o 1 Qt n

n p Qtfp p Qt1 1 o CHILOQUIN e C 7/1/05-2 s r Qc 40 a 97 fi Qc n 121°10’

m e DAM Qc l yo 7/1/05-1

a d n i Qsf l Qt1 Qt 10 l D 1 7/2/05-1 i Qtf r W a Qtfp w Qmvf Qtfp Qtf Qt1 Qsf Qfp k ee Qt Qt r 1 1 Qsw C y 121°50’ e Qtf 121°30’ n Qt k 1 c Qc L o o n D 9/12/06-1a g

B C u r t k ee te Qtf e k Qt s 9/12/06-2, 3 e 1 r k C e o e f e r 45 Qtfp k Qtf SPRAGUE RIVER ROAD a C l t Tbr n y

h S r e S e Saddle Mountain Qc

Qsf y M Qt

1 Qc c G Qtf

Qt 5 a 1 o Qc Qtfp 42°30’ d Brown n

s Qfu Qtf Wild R Qmvf Spring Tbr i Qsf Qc Qc Billy Qsw v 9/22/05-3, 4 e F Qt1 Lake r iv 42°30’ em Qtf Qc Qfu Qtfp il Qtf e C Qfp reek k Qt3 Qc 5 ree Qf 6/25/07-1, 2 Qtf 121° t C Qf1 2 9/22/05-6 Qmvf 6/28/07-1 Qc ou N r Qtfp ague R Tbr N o T r iver Qc Knot Tableland Qtf o r 9/22/05-1, 2 50 p Tbr 11499100 rt Qtf Qfp Qc t S Qc Tbr h h Qt2 Qt1 Qtf Qt2 Tbr F Fo ek o Sprague rk Trout Cre Qt Tbr Qc Qmvf Qc Knot Tableland Qfu rk Riv Qc Qtu 1 6/22/07-4, 5 er Qt1 Qtfp Qt1 Qtfp Qt4 Qsf Qc Qt Qc Qc Qtfp Qf 1 Qtfp Qt 2 Qfp Qsw Ferguson Qtf 1 55 Qc Qtf Qtf Qtf 7/24/07-1, 2 Mountain Qtf Bad Lands Qc 0 k Qtf Qtf Qmvf e Qmvf Qmvf Qtf 9/14/07-1 e 6/28/05-1 Qtfp Qfp r Qt1 Qc 70 C Sp Qtfp Fritz Cr t Qf Qmvf ra Qfp e u Qfu 2 Qmvf Qfp gu Qc Qc 6/26/07-3 ek 121°40’ o 65 e Tr 60 Qtf Qfp k Qtfp Qtf Qtf For Qc Qt Qc Tbr th Qmvf 1 River Medicine Qtf ou Qtfp 75 Qmvf 0 S Sprague River Council Qmvf 9/13/07-3 Springs 9/13/06-3 Qsw Tbr Qc reek 17.2 Qmvf 80 Qtf C Qc Qf3 g Butte Qmvf 11497500 n Qsw Qc Qc i 90 m Qw Qtfp Qtfp Qt e Qtfp Qc Qw Tbr Qc 1 S Braymill Qt Qtf Qt Qt p Qfp D Beatty 1BeattyQt Gap Qt1 1 1 r Qtf 2 Qt1 9/13/06-1, 2 ag Qf2 Qfu Qtfp u Qtf Qtfp 85 e 95 Qtf Qf Qtf Qtf River 1 Qf SPRAGUE RIVER ROAD Tbr Qc Qc 32.4 3 Qw Spring Kamkaun Qtfp Qtf Qc Qc Qf Tbr K Davis Hill Qc Qf1 Qtf 11.4 Qf3 4 Qf4 Butte Chiloquin Spring Qtf Switchback Hill Qf4 Qtf Qf4 Canyon Qfu Qw Tbr Qc Coyote Qfu Bug Qfu Qf Campbell 0 Qf Qc 1 Bucket 4 Reservoir Qf3 Qfu Butte 11495600 B S’Ocholis k Qtf Qf e r Medicine 4 o e Canyon r Qfu w Mountain 6/23/07-1 42°25’ C n Qtf 10.6 100 k C S c r o Lower o e u 48.2 e th Sycan R k Qtf 9.8 42°25’ SQUAW FLAT ROAD Qtfp Qc F North W or h k Fork is Qfp ky S 58.0 C pr r Qtfp ag 0 B ee u ly Qtfp k e Buttes of 0 Bly Devil’s R Qc iv the Gods er Council Butte Beatty Gap Upper Garden M Bly Ridge Qtf Beatty o 76.8 Valley South u Sycan n Qc t Fork a 105 81.0 in Qtfp 89.6 93.2 Cliney Round Flat Qc Mountain Qtfp 140 F P i a s r h a ho d le i se C C r 140 e re 106.3 e e GEOMORPHIC FLOOD PLAIN STUDY REACHES k k 121°30’ 121°20’ 121°10’

Qtfp 0 2 4 6 8 10 MILES

0 2 4 6 8 10 KILOMETERS

SCALE 1:100,000 121° 42°20’

Base compiled from Watershed Sciences, Inc. (2005) digital data, 1-meter resolution (along valley floor); Geologic linework was digitized at a scale of 1:3,000 but the accuracy U.S. Geological Survey digital data, 10-meter resolution (outside valley floor). Coordinate reference system: of the contacts varies depending on location and geomorphic unit. Universal Transverse Mercator projection, Zone 10N, horizontal datum is North American Datum of 1983. Geomorphic Surfaces of the Sprague and Lower Sycan Rivers, Oregon By Jim E. O’Connor, Patricia F. McDowell, Pollyanna Lind, Christine G. Rasmussen, and Mackenzie K. Keith 2015