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HomeMy WebLinkAboutAgenda Report - March 21, 1990 (45)P Mr. Joshua A, Horner 1228 West Mendocino Avenue Stockton, California 95204 March 7, 1990 Lodi Citys-Council 221 West Pine - - - Lodi, California 95240 Dear Councilmembers: 01 behalf of the San Joaquin Audubon Society, I an writing today to encourage you to adopt a resolution which would recognize the value of, and recommend, a study concerning the intrinsic benefits of preserving the natural status of the riparian wetland area along the north bank of the Mokelumne River between Highway 99 and Woodbridge. Although we recognize the necessity of development, as conservationists, ve feel that careful and thoughtful long-range planning is essential to preserving the quality of life that we all hope to enjoy. Riparian habitats are unique natural areas which support a great diversity of both plant and animal life. Additionally, the river and its natural borders have immeasurable aesthetic and recreational value. Unfortunately, according to a 1981 study (enclosed) which waspresented in a paper to the California Riparian Systems Conference,, of the approximately 41,300 ha. (102,000 ac.) of riparian forest that remain in the Central Valley, approximately 19,800 ha, (49,000 ac.) were in a disturbed and/or degraded condition based upon the riparian mapping cateory code, and the other 21,500 ha. (53,000 ac.) was then and is still today being heavily impacted by human activities. Revegetation of damaged riparian zones can be implemented to restore nativelant species and enhance wildlife as demonstrated by the Nature Conservancy Cosumnes River Preserve near Twin Cities Road. However, such restoration is much more costly than simply preventing the damage from occurring in the first place, Therefore, vie support the long-term preservation of presently undeveloped areas of the Mokelumne River and bordering habitat for the benefit of wildlife and local citizens now and in the future. We urge you again to adopt such a resolution. If the San icaq xin Audubon Society may be of any assistance to you regarding this matter, please feel free to contact ne at (209) 465-6188. Thank you. Sincerely, 'j�w�k✓ a Joshua A. Horner Member, Board of Directors San Joaquin Audubon Society A BRIEF HISTORY OF RIPARIAN FORESTS IN M E CENTRAL VALLEY OF CALIFORNIAI Edwin F. Katibah2 Abstract. --Riparian forests once occupied substantially greater areas in the Central Valley of California than they do today. This paper explores the hydrologic influences which allowed the original riparian forests to establish themselves, the extent and reasons for the decline of the pre -settlement forests, a� well as an estimate of the extent of today's remaining forests. INTRODUCTION One hundred and fifty years ago, Califor- nia's Central Valley was endowed vith a natural environment the scope and magnitude of which it is difficult, if not impossible, to fully compre- hend today. Two major river systems, the Sacra- mento and the San Joaquin, drained the Valley. Flooding in the winter and spring. these rivers and their tributaries formed vast flood basins and huge, shallov seasonal lakes. Marsh vegeta- tion (primarily Scirpus spp. and Typha app.) occupied these wetter sites. Extensive perennial grassland (Stipa spp,) and scattered valley oak (Quercus iobata) woodlands were found on the drier uplands. while the southern end of the Valley had large areas of saltbush (Atriplex spp.) desert. Through all of these vegetation communities, along the major river and stream systems. were strips of dense forest. These riverine, or riparian, forests developed on the natural levees of river -deposited silt, lining most of the Valley's drainages. Riparian forests are structurally and flor- istically complex vegetation communities. These forests are difficult to characterize, for they occur in many d-ifferent forms throughout :he Valley. Under ideal conditions, these forests consist of several layers vith dense undergrowth, similar in some cases to tropical jungles (Holmes 'Cl al. 1915). bremont cottonwood (Populus fremontii), California sycamore (Platanus racemosa), willow (Salix spp.), and valley oak are common upper canopy species found throughout the Valley. Such species as box elder (Acer negundo subsp. californicum), Oregon ash (Fraxinus latifolia), and various species IPaper presented at ti,e CaIif.;rni.a Riparian Svsteens Con erenCr:e . (ti ntrstty or Cali:grii,t.D:r:ts, Septomber 17-1Q, 1981 . -Fdwt n F. ria* i baa i: a;: A ;,,c i at •• SP.-Cialiit, D) par ta,.•nt ,.,i ry and R••s,>u:'...• M3naiement. Cniversi;v ut lalt:urnIt. 5orke-lo of willow generally occur in intermediate layers. Vines (lianas) are characteristic of many ripar- ian forests, vith wild grape (Vitis californi- sa), poison oak (Rhus diversiloba), Dutch- man's pipe vine (Aristolochia californica), and wild clematis (Clematis spp.) growing through the various layers. Riparian forest undergrovth has a very diverse flora which varies widely throughout the Valley. Too nany character- istic undergrowth plant species occur to mention but a feu: mugwort (Artemisia douglasianai) mulefat (Bacrharis viminea), wild rose (rtosa californica), and blackberry (Rubus spp.). Riparian forests have bean greatly reduced or eliminated throughout Each of the Valley. Ecologically they continue to play an important role with many plant and animal species dependent %n them. Riparian forests are popular recreation sites, providing s vide range of beneficial values Cor the Valley's populace. These facts, among ochers, have recently aroused an interest in riparian forest ecology and management by both the general public and various Federal, State, and local agencies. This new interest has promp- ted questions as to why these forests occurred more along some river systems than others; how extensive the pre -settlement forests vere; vhat caused their decline; and hov many of these for- ests remain today. This paper attempts to pro- vide a brief. informative look into these ques- tions. HYDROLACY OF THE CENTRAL VALLEY There is significant hydrologic diversit} throughout the Central Valley, and it was this diversity which vas in part responsible for dif- ferenc,-s ',etwee n individual riDari-in forests. FOC•x 3mn!' the •.'.al lev has Iwo mi jar rlv,•rine hydro! ,_. _ that of the S.icram•rnto V- 0 -ley _ .. ^., nt is north and ": the San .ioa•.t.Iia V3!iry . -p>nent in tie ,.,uth. lh., influenc.•, ... rhes•.• r; ,r `I. 'r,lokiC t••r., ,xi th., natur•.• of the riparian forests associated with them were profound. Figure 1 depicts the Central Valley and its major surface hydrology as it may have appeared under pre -settlement conditions. same.rmo n«« a e�•en« ia.« c i `z r r.a m.« s' �1 t��anwle.nwiw. `� Figure 1. --Surface h+ urology of the Central Val- ley as it may gave appeared around 1850. Areas in black within the Tulare Subbasin represent seasonal lakes. Shaded areas, shown throughout the Valley, indicate flood basins and freshwater marshes. Hydrology of the Sacramento Valley The Sacranento Valley is bordered by the mountains of the Coast Ranges to the vest, the Klanath and Cascade Ranges to the north, avid the Sierra Nevada to the east. To the south, the Sacramento Valley joins the San Joaq.lin Valley at the 5acramentofSan Joaquin River Delta. The comparatively dr:' interior Coast Ran;te mountain, haves no lar;te rivers draining into the Vallev. Only strrnms, sone O! the larrer boing Caches, and Puz1h Creeks. The Sacrament,) River originates in tie K13-ndt}t Y,,iuntains and is joi:l•t by two rivers. the M.cl loud and th. i'it ,I, rte: is now Shasta Lake. The Sierra Nevada mountains to the east provide the greatest number of rivers and major streams .:raining into the Sacramento Valley --the Feather, Yuba, Bear, and American Rivers, and Butte and Big Chico Creeks. Numerous other streams also flowed into the Sacramento Valley from the surrounding mountains. Not all of these streacs actually reached the Sacramento River. Historically, natural levees and naturally occurring flood basins prevented some streams from reaching the main rivers. In- stead, these streams spread out "through a welter of distributaries" (Thompson 1961) on the Valley floor. These distributaries typically ended in "sinks" of tule marsh. Putah, Cache, and Butte Creeks are among those streams which never joined the main river network in the Sacramento Valley. The Sacramento Valley and its surrounding foothills, unlike the San Joaquin Valley region, receive substantial rainfall in the winter and early spring. This resulted in Sacramento Valley rivers experiencing maximum flows from December through March instead of May and June as is char- acteristic of most western rivers, including those in the San Joaquin Valley (Fortier 1909). Snowmelt fortified the river flow in the Sacra- mento Valley through the late spring. Annual su—r drought brought the low flow rates found in these rivers through late fall. During the peak flows of the Sacramento Val- ley rivers, the flood basins were filled by sediment -carrying waters. The natural levees dividing the flood basins from the major rivers were initially developed and then augmented by this annual flood cycle. Impressive natural levees along the Sacramento River, "...from 5 to 20 feet above the flood basins..." and 1.6-16 km. (1-10 mi.) in width, averaging 4.8 km. (3 mi.), ..formed corridors l* generally dry land during times of flooding.. . (Thompson 1961). The other major Sacramento Valley rivers and streams also formed well-developed natural levees. Hydrology of the Sae Joaquin Valley The San Joaquin Valley is bounded by the flat relief of the Sacramento/San Joaquin River Delta to the north, the mountains of the Sierra Nevada to the east, the Coast Ranges to the west, and the Tehachapi `fountains to the south. The Coast Ranges and the Tehachapi Mountains bordering the San Joaquin Valley are very arid. Thus. the streams which originate from these mountains were characteristically intermittent in flow. Probably the most notable of these inter- mittent streams was Los Catos Creek. whose allu- vial fan nslped fora the Tulare Subbasin, a major in'luanc•e :n the hydrology of thi San Joaquin :'al 1 e v . Num^ ius Si.•rrl rivers and streams tI1wed 'at 1 the an ;naq:; V-11 1.-V, including the Cum lrtnu.,+•• '�•'r, iuti..•• (:a; ivora, St.inlsIaus, Tuo- iui:l:l.• •'.: ChowebI l la r ­ ;no San Joaqul n, Y,In,;s, F:au•-a:l. meced WNW 41,1te and .,ern R1v•srs. San ,w.ern Awe, Kim" pkW r J a rw a.« A F C z 1 Kam Wv« Figure 1. --Surface h+ urology of the Central Val- ley as it may gave appeared around 1850. Areas in black within the Tulare Subbasin represent seasonal lakes. Shaded areas, shown throughout the Valley, indicate flood basins and freshwater marshes. Hydrology of the Sacramento Valley The Sacranento Valley is bordered by the mountains of the Coast Ranges to the vest, the Klanath and Cascade Ranges to the north, avid the Sierra Nevada to the east. To the south, the Sacramento Valley joins the San Joaq.lin Valley at the 5acramentofSan Joaquin River Delta. The comparatively dr:' interior Coast Ran;te mountain, haves no lar;te rivers draining into the Vallev. Only strrnms, sone O! the larrer boing Caches, and Puz1h Creeks. The Sacrament,) River originates in tie K13-ndt}t Y,,iuntains and is joi:l•t by two rivers. the M.cl loud and th. i'it ,I, rte: is now Shasta Lake. The Sierra Nevada mountains to the east provide the greatest number of rivers and major streams .:raining into the Sacramento Valley --the Feather, Yuba, Bear, and American Rivers, and Butte and Big Chico Creeks. Numerous other streams also flowed into the Sacramento Valley from the surrounding mountains. Not all of these streacs actually reached the Sacramento River. Historically, natural levees and naturally occurring flood basins prevented some streams from reaching the main rivers. In- stead, these streams spread out "through a welter of distributaries" (Thompson 1961) on the Valley floor. These distributaries typically ended in "sinks" of tule marsh. Putah, Cache, and Butte Creeks are among those streams which never joined the main river network in the Sacramento Valley. The Sacramento Valley and its surrounding foothills, unlike the San Joaquin Valley region, receive substantial rainfall in the winter and early spring. This resulted in Sacramento Valley rivers experiencing maximum flows from December through March instead of May and June as is char- acteristic of most western rivers, including those in the San Joaquin Valley (Fortier 1909). Snowmelt fortified the river flow in the Sacra- mento Valley through the late spring. Annual su—r drought brought the low flow rates found in these rivers through late fall. During the peak flows of the Sacramento Val- ley rivers, the flood basins were filled by sediment -carrying waters. The natural levees dividing the flood basins from the major rivers were initially developed and then augmented by this annual flood cycle. Impressive natural levees along the Sacramento River, "...from 5 to 20 feet above the flood basins..." and 1.6-16 km. (1-10 mi.) in width, averaging 4.8 km. (3 mi.), ..formed corridors l* generally dry land during times of flooding.. . (Thompson 1961). The other major Sacramento Valley rivers and streams also formed well-developed natural levees. Hydrology of the Sae Joaquin Valley The San Joaquin Valley is bounded by the flat relief of the Sacramento/San Joaquin River Delta to the north, the mountains of the Sierra Nevada to the east, the Coast Ranges to the west, and the Tehachapi `fountains to the south. The Coast Ranges and the Tehachapi Mountains bordering the San Joaquin Valley are very arid. Thus. the streams which originate from these mountains were characteristically intermittent in flow. Probably the most notable of these inter- mittent streams was Los Catos Creek. whose allu- vial fan nslped fora the Tulare Subbasin, a major in'luanc•e :n the hydrology of thi San Joaquin :'al 1 e v . Num^ ius Si.•rrl rivers and streams tI1wed 'at 1 the an ;naq:; V-11 1.-V, including the Cum lrtnu.,+•• '�•'r, iuti..•• (:a; ivora, St.inlsIaus, Tuo- iui:l:l.• •'.: ChowebI l la r ­ ;no San Joaqul n, Y,In,;s, F:au•-a:l. 1'u la, 41,1te and .,ern R1v•srs. The San Joaquin Valley is itself divided into two distinct hydrologic subbasins: the San Joaquin and the Tulare. The San Joaquin Subbasin is drained by the San Joaquin River; the Tulare Subbasin has no perennial surface outlet. The Tulare Subbasin was formed at the south end of the San Joaquin Valley by the merging of alluvial fans from the Kings River to the east and Los Gatos Creek to the west (Cone 1911). Mater originating from the major Tulare Subbasin rivers --the Kings, Kaweah , Tule , White, and kern --flowed into this subbasin and found no nor- mal outlet to the sea. Instead, large inland I formed --the Tulare, Buena Vista, Kern, and Goose. These largely temporary lakes. extremely shallow as they flooded the nearly flat land- scape, rose dramatically as winter and spring runoff filled them. As the seasonal lakes filled beyocd capacity they flowed into one another, finally rising above the natural alluvial bar- riers which divided the Tulare and San Joaquin Subbasins, sending tremendous quantities of water down the Fresno Slough into the San Joaquin River. Later in the season, after the overland flow of water had ceased, substanti_: quantities of water were still drained from the Tulare Subbasin into the San Joaquin River via subsurface flow. This underground accession may have doubled the San Joaquin River's volume (Irrigation in Cali- fornia 1373). This undoubtedly helped to main- tain the flow of the San Joaquin River in its southern reaches during the long, dry California :,.--niers. The San Joaquin Valley rivers, whose waters were primarily snowmelt, tended to reach maximum floe in May and June. In contrasc, peak flow of the Sacramento was usually in March, although some of the major peak flow rainfloods have occurred much earlier in the winter (1955-56 flood - -December and January; 1964-65 flood -- December and January; 1970 flood --January). In addition, the San Joaquin River's flow into the Delta in its peak flow period was less then one- half the discharge rate of the Sacramento River during its usual peak flow period In March. De- spite this difference in peak flow timing. r'ne two rivers discharged approximately equal amounts of water into :he Delta. San Joaquin Valley rivers and streams in some instances did not produce the large. natural levees characteristic of the Sacranento Vallry. ?eak water flows in San Joaquin Valley rivers and itreams were typically less than those in the u ramento Valley, thus limiting thnir ability to pick up and carry sediment for great distances. at ural levers did firm along the rm i it nnrtht>rn :.an Joaquia Valley ri er;--t 1P Tuol'imnr, stani,- :IUC, M••-c.•d. Mok,'1::^In,', CosumnNi• and :sort:wrn ift Joaquin. ,. . , in -i ..n 1v i. n r •. r .-n: ..i. i --v r a i:.. ...irl. h:.,r r is third in peak flow after the Tuolumne and Kings Rivers (Cone 1911). Relativelj low-energy perk flows resulted in suspended sediment deposition and natural Ievee formation only where it first entered the Valley. From there until it reached Freano Slough. the San Joaquin River received no :dace tributaries. Ac that point it received the surface floodwater flows through the Fresno Slough from the Tulare Subbasin and the under- ground flow through t'., . extensive Tulare Subbasin aquifer. Both of these flows were substantial, but both lack, -d significant sediment content. The overland :low through Fresno Slough had already deposited its sediment load in the shallow Tulare Subbasin lakes. The subsurface waters had been filtered of any sediment long before they joined the San Joaquin River. Thus while the southern San Joaquin River gained a large water accession, especially during the peak spring flood, it was unable to build any significant natural levees because of the low sediment load. With no natur- al levees to contain its waters. the San Joaquin River spread out over the flat Valley floor, sustaining the large freshwater marshes st ill found there today. The first major sediment - carrying waters to reach the San Joaquin River for many miles occurred at its confluence with the Merced River. From here to the Delta, sub- stantial natural levees were built along the San Joaquin River. The Tulare Subbasin rivers developed natural levees where there rivers first entered the Val- ley. The shifting courses of these rivers un- doubtedly allowed many miles of levees to be formed. though they were quite narrow and con- fined ce.npared to the levees of the Sacramento Valley :fivers. EXIENT OF PRE -SETTLEMENT RIPARIAN FORESTS While the largest snd mist diverse riparian forests occurred on rivers having natural levees, wel 1 -developed riparian systems were found along virtually all watercourses in the Central Valley. Most riverine floodpiains supported riparian vegetation to about the 100 -year flood line. Virtually all watercourses supported dense vege- tation from the water's edge to lite outer edge of the riparian (mist soil) zone. whether or not natural levees were present. The overall pre - settlement riparian vegetation pattern was one of stringers or corridors of dense, mesio, broadleaf vegetation of varying widths bounding the vator- cuures, the widths being; determined by local :rydro:ogic and landform characteristics. Ac::)rJi�i,; t.> vari.-ms accounts, the sacram,-n- ., •ti 7: lev ha,: 324.000 tia. !801),000 if rip ar i in for.. ini -fig is t •r 1! rl , I: ;.In ,1 conservatively estimated that the Central Valley had greater than 373 000 ha. (921,000 a,:.) of riparian forest under pre-s-ettlment conditions. How's =p is based on early soil maps and covers on area in the Central Valley from the Sacramento River at Redding in the north to the Merced River in the south. I measured for areal Atent the presumptive riparian forests shown on Hme's map. This estimate, presented in table 1, yields a value of 312,100 ha. (771.600 ac.) of pre -settlement riparian forest. This value must be considered conservative for that area, as Hove's map depicts only the large, contiguous riparian forests. The many smaller areas of riparian -indicator soil -types were belov the mapping level of the historic soil maps used in the presumptive -riparian -forest map preparation. 19 In addition, Hoven map exnludtd the south- ern rivers of the San Joaquin Valley --the San Joaquin below its confluence with the Merced; and the Kings, Kaweah, Tule, and Kern. The above figure reflects that exclusion. I judged the riparian systems associated vith those rivers to have totalled an estimated 20.200 ha. (50,000 ac.) (table 1). Furthermore, I estimated ap- proximately 60.500 ha. (100,000 ace) to account for the riparian forest vegetation present along the small streams, sloughs, lakes, ponds, and marsh borders throughout the entire Central Valley (table 1). These estimates are undoub- tedly quite conservative and subject to consider- able refinement . Table 1, --Estimates of areal extent of pre -settlement ripaiian forests in the Central Valley of Califor- nia. Estimated site ha. Forest name Description (ac.) Ceatral Valley Riparian Forest Area Estimated From Hove `tap Upper Sacramento River Sacramento River from Table Mountain to near 17,500 Redding (includes forests along Cottonvood, (43,200) Stillwater, and Cov Creeks). Big Bend Sacramento River in the vicinity of Big Bend. 800 (2,000) Antelope Creek Antelope Creek east of Red Bluff. 300 (700) Sacramento River Sacramento River from belov Sacramento to 206,000 above Red Bluff (includes Elder, Mill, (508,800) Thornes, Deer, Rice, Stony, Pine, Rock, Big Chico. Little Chico. Butte, Hone ut , and Cache Creeks; Feather, Yuba, Bear, and American Rivers). (Near) Knight's Landing An area near Knight's Landing 500 0 ,300 ) Putah Creek Putah Creek from above Winters to the Putah 8,900 Creek Sirks. (22,000) Dixon An area in &hevieinity of Dixon. 2,200 (5,400) Lower Sacramento River Sacramento River below Courtland. !,100 (2,600) Cosumnes/Mokelumne Rivers Upper reaches of Cosumnes and Mokelumne 23,400 Rivers so below their confluence. (57,800) Calaveras River Calaveras River north of Stockton. 9,500 (23,500) Upper San Joaquin River San Joaquin River vest of Stockton. 300 ( 700 ) San Joaquin River San Joaquin River from its confluence with 36,700 Merced River to just outside Stockton (90,600) (includes X,,rced River, parts of Stanis- htis -end Tuol inne Riv,?rs). Middle Tuolumne River Midd 1 • T.eolum-u- 4tvar near Mod. -sr-.). 3.. 1 U (7.700) 7pper Tuolumne River ::pp,'r Tuol snn•• ?i:.•r ir-i whoro it ont,•rs t�iv 2,100 .5.300) ;',hUU) ra- Table 1 ---Estimates of areal extent Of pre -settlement riparian forests in the Central Valley of Califor- nia (cont.). Additional Riparian Forest Area Based On Estimates By Katibah South San Joaquin Valley Series of forests along major southern San 20,200 Joaquin Valley rivers (includes upper San (50,000) Joaquin, Chowchilla, Fresno, Kings. Kern, and Tule); and the alluvial floodplains from these rivers. Miscellaneous Riparian forest present along small streams 40,500 and sloughs; and lake, pond, and marsh (100,000) borders throughout the entire Central Valley. Total 60,700 (150,000) Total Estimated Pre -Settlement Central Valley Riparian Forest Area 373,100 (921,600) 'Based on a map by J. Greg Howe (Roberts et a2. 1977) and estimates by E. Katibah. DECLINE OF CENTRAL VALLEY RIPARIAN FORESTS "No natural landscapes of California have been so altered by man as its bottomlands" (Bakker 1972). The once -Lush riparian forests, forming natural vegetation corridors along many of the Central Valley's watercourses. are mostly gone today. These forests were, in Thompson's words, "...modified with a rapidity and complete- ness matched in few parts of the United States" (Thompson 1961). The reasons far the rapid decline of this once extensive ecosystem are not hard to find; one needs only to review the cultural history of the Central Valley for :he last 150 years. Prior to 1822 the land known as California was claimed and ruled by Spain. Little develop- ment occurred during this period, and at the cessation of Spanish rule in 1322 only about 30 ranches or farms had been granted in California (Fortier 1909). Mexico Assumed control of Cali- fornia until 1848. By ... 1846 no less than eight hundred large tracts containing some of the best land in the State had been given away" iLid.). The character and size of the large Xexizan land grants had a prafound influence on the social, commercial, and agricultural develop - cant of the Central Valley (ibid,), development .+hich would ultimataly and adversely affect ri- pirian vegetation. With the annexation of California to the 'nft,�d Stat;as in 1348, rapid d.ev•:lopment ,,f the ••ntral ':ailey be4an. The Gold 'Rush. brginnint; 1 :440- exerted •.nor.zous land u, • pr.•.t;ur•.; .ind rapid and ;t:t:-n unp' anne.e d_•:•ri.tpa•• It .: . :t:l•ty. •l.!alfis UlT ,,.•� in tilr r: • IV 1r •o their fortunes in the gold -bearing Mother Lode rivers and streams soon found that agriculture provided a much more stable and practical exis- tence. The riparian forests. often the only significant woody vegetation on the Valley floor, were utilized by the growing agricultural commu- nity for fencing, lumber, and fuel (Thompson 1961). Steamships using the Sacramento River were also heavy users of local wood fuel. Knight's Landing on the Sacramento River was a site where cordwood was loaded onto these ships. It has been speculated that this wood came from the Cache Creek and Sacraaento River riparian forests because Knight's Landing is adjacent to the tree- less Yolo flood basin This supplying of fuel wood to the numerous woodburning vessels on the Sacral nto River must have made a signifi- cant contribution to the early destruction of the loca', riparian forests (ibid.). As early a:; 1868 the general scarcity of woody vegetation was noted in the Valley by some of its inhabitants (ibid.). The pressures on riparian forest vegetation continued as farmers found tnat the soil on the natural levees was highly fertile. easily managed, and not subject to the seasonal flooding of nearby lower -lying ground (ibid.). As agriculture expanded in the Central Valley, water demand began to exceed water .supply. Farmers also found that the :`alley had too mucn water in the winter and sprinv, and not enou,;h In the summer. 4atr.r devr-lopment and r,•rinmation projects vera started, primarily for s;:ri:.ulturr and communtty flood pra.)tr.ction, and r-midl+ eliminated manv tr the l'al ley's native 1 tnd systems. 'Ci r,. a!ri-ulturrll ••xpan=t citi.•s ;;r.•.• ;o . ?.1 rt .:I. ..w in.lw;try. %a[:: :allev T •W -I. .tad . ; i •'• 1 - r , ti :: i t in .. .n-; ;> : -Ind tpan ,. S:t.-r t--...1• .:u! f ••- .. .I re.n.•n- _ :•;; ... -.. ..,. the tiu:l M ing of levees around the town, "...set the course Cor Valley development over the next several generations" (Karhl 1979). To promote the recla- mation of the tule marsh and floodplain lands, the Arkansas Act of 1850 was applied in Califor- nia. This act gave the State of California mil- lions of acres of federally owned floodplains, provided that the State drain and reclaim these lands. Skee Arkansas Act of 1850 stipulated that all manmade levees were to be constructed along natural drainage systems. The Green Act of 1868, passed by the California Legislature, however, freed the reclamation process of most controls. The effects of the Green Act were devastating to riparian forests, Levees were built for the con- venience of landowners with little or no regard for the natural hydrologic systems. Remaining ripariaa forests, occupying natural levees along river courses, Here destroyed in the quest to protect lands from flooding. As in the Sacramento Valley, artificial levees were built along major San Joaquin Valley rivers. San Joaquin Valley agriculture faced dif- ferent water -related problems. Winter and spring rainfall there is substantially less than in the Sacramento Valley, thus Saa Joaquin Valley land needed to be irrigated if it was to reliably pro- duce crops. With the Green Act as guiding legis- lation. Dore than 1,500 km. (1,000 mi.) of irriga- tion canals were developed by 1878 in Fresno County alone (ibid.). In the following years. and continuing up to the present time, numerous and controversial water projects have been the hallmark of Central Valley development. The demand for water, so tied to the agricultural, commercial, and urban development of the Valley, was, at least indirect- ly, responsible Cor the degradation of many of the remaining riparian forests. Artificial levees, river channelization, dam building, water diversion. and heavy groundvater pumping vere amonp, the factors which reduced the original riparian forest to the small, scattered remnant forests found today. PRESM ElrM OF REPMANr RIPARIAN FO RE S i S n 1979, the Geography Departments of Cali- fornia Stare University, Chico, and California State University, Fresno, under contract co the California Department of Fish and Came, compiled riparian vegetation distribution claps for the Cen- tral Valley (Nelson and Nelson 1983). This map- ping effort provided an essentially complete in- ventory of all extant riparian v-getatipn (not just mature forest) in the Central Valley,' M Central Valley riparian ruppinz project. 1979. lnc• rprrtat ion and rlappint: Re— p.... pr.•pa:-'d by the Hipari.ln Mappink: . "1-, G,'o�:- r:^nv i:alltorni1 St it i'n1':•'r•:i: V . 1:1 C`i,• [).•�.3rt'::.'RC i...., r.i {'�l': Cii1: . • th. i -.ti 1 ... '11.1 :). pari:n.•r,i . ..1:.n i n,; lir i::..:i , sa: r 3M -/lt. W Using these maps. the areas and lengths of riparian systems were falculated on an individual cap and county basis. Even though there is no explicit riparian forest category on these maps, applicable classifications vere determined which should represent riparian forests. Using this approach, it was determined that approximately 41,300 ha. (102,000 ac.) of riparian forest remain in the Central Valley today (Katibah et al. 1983). Of the 61,300 ha. of forest, approximately 19,800 ha. (49.000 ac.) are in a disturbed and/or degraded condition based on the riparian mapping category code. Approximately 21,500 ha. (53,000 ac.) vere identified as mature riparian forest, with no indication of condition. However, based on recent research findings (Katibah et al. in press), it can be surmised that the majority of these 21,500 ha. of mature riparian forest have been and are currently being heavily impacted by human activities. XC ONAttof-IJ A]2 The complex hydrologic systems found in the Central Valley of California under pristine con- ditions art gone. The original riparian forests, dependent on the diverse Valley hydrology, are likewise gone for the most part. Today's ripar- ian forests are in a precarious position as the demand for greater land utilization by the agri- cultural industry and the spread of urbanization threaten the remaining forest tracts. Offsetting this trend, however, is a greater apreciation of the values (economic and nonecono- mic) of riparian forests by Valley landowners and the general public. Riparian forests are present in some of the finest and most popular parks in the Central Valley. These forests provide habi- tat for many of the Valley's wildlife species. They also contain numerous and diverse native plant species. These values, among others, must compete with the most complex and controversial issue of all: vater. in California as in the rest of the Vest, water equals development, and California does not have adequate water to meet its antici- pated future demands. Hov the remaining riparian forests will fare in the future is not known. As interest in and knowledge about this resource develops, and as hindsight provides an understan- ding of the past, it is hoped that a reasonable compromise can be achieved between this unique and valuablt, resoure and the needs of society. 5Katibah, F;. F. ;:.E. Ned Off, and K. J. Durmer. 1980. The areal and linear x r + n t of riparian v --;tet at ion in' the G:ntraI :'31iey of California. Final r•,port to th-! California i)e— parr:aant of Fish and PIinninti 13r-3n.h. &•'^,,1.• S"n -.Inc aril ram, Dep Irtmen: of ry a:1d R • , nit : i.: ..,•n; I: r.::.... _ , of Ca..l.:r::13 1, .. LITERATURE CITED Sakke r. Elna S 1912. An. island called Califor- nia. 357 p. tniversity of California press, Berkeley, California. Cone, Victor M. 1911. Irrigation in the San Joaquin Valley, California. USDA Office of Experiment Stations. Bulletin 239. 62 p Government Printing Office, Uashington, D.C. Fortier, Samuel. 1909. Irrigation in the Sacra- aento Valley, California. USDA Office of Experiment Stations, Bulletin 207. 99 p Government Printing Office, Washington, DC Holmes. L.C.. J.W. Nelson, and party. 1915. Re- connaissance soil sorvey of the Sacramento Valley, California. USDA Publication. Government Printing Office, Uashington, D.0 Irrigation in California: the San Joaquin and Tulare Plains, a review of the whole field. 1873. 22 p. Record Steambook and Job Printing House, Sacramento, California. Kahrl. William L 1979, The California mater atlas. Prepared by the Gove►har's Office of Tanning and Research in cooperation with the California Deportment of Water Re- sources. 113 p Sacramento, California. Katibah, Edwin F., Nicole E fedeff, and Kevin J. Dummer. 1963. A summary of the riparian vegetation areal and linear extent measure- ments from the Central Valley riparian map- ping project. In: RE Warner and KN. Hendrix (cd.). California Riparian Systens. (university of California, Davis, September 17-19, 19811. University of California Press, Berkeley. N Katibah, Edwin F., Kevin J. Dummer, and Nicole E. %edeff. In press. Evaluation of the ripar- ian vegetation resource in the Central Vallev of California using remote sensing techniques. Proceedings of the ASP and ACSM fall technical meeting. (San Francisco. California, September 9-11,1981). Nelson, Charles W., and James R Nelson. 1983. Central Valley riparian rapping project. In: R.E. Warner and K.H. Hendrix (ed.). California Riparian Systems. [University of California. Davis. September 17-19, 1981). University of California Press, Berkeley. Roberts, W.G., J.C. H W e , and J. Major. 1977. A survey of riparian forest flora and fauna in California. p 3-19. In: A Sands (ed.). Riparian forests in California: their ecol- ogy and conservation. Institute of Ecology Publication Bb. 15. 122 p University of California, Davis. Smith, FE 1977. A short reveiw of the status of riparian forests in California. p. 1-2. In: A Sands (ed.). Riparian forests in California: their ecology and conservation. Insticlite of Ecology Publication Db. 15. 122 p Liiversity of California, Davis. Thompson, K. 1961. Riparian forests of the Sacramento Valley, California. Annals Assoc. of Amer. Geog. 51:294-315. Q CITY COUNCIL JOHNR. (Randy) SNIDER. Maya DAVID M.HINCHMAN Maya Pro Tempore EVELYN M.OLSON JAMESW. PINKERTON. Jr. FRED M. REID 6_ , CITY OF LOOM CITY HALL, 221 WEST PINE STREET CALL BOX 3006 IQJI. CALIFORNIA 95241-1910 (209) 3345634 TELECOPIER : (209) 333.6795 March 28, 1990 Mr. Joshua A Horner Member, Board of Directors San Joaquin Audubon Society 1228 West Mendocino Avenue Stockton, CA 95204 Dear Mr. Horner: THOMAS A. PETERSON city Manager ALICE M. REIMCHE city Clerk BOB MCNATT City Attorney Thank you for your letter expressing concern regarding the undeveloped area of the Mokelumne River between Woodbridge and Highway 99 and urging maintaining the natural status of this riparian wetland. The City of Lodi i s presently i n the process of updating i t s General Plan. This matter was a subject of discussion on the Open Space Element of the Lodi General Plan. The Parks, Recreation and Open Space Element of the General Plan was discussed at a Special Meeting of the Lodi City Council and the Lodi Planning Commission on Wednesday, February 28, 1990. Should you have any questions regarding this matter, please do not hesitate to call this office. ry ruly_ _vours, 11 ri John Ru (Randy) Snider Maynr, City of Lodi JRS/AMR/jmp