May 9, 2002

January 5, 2005

Leslie Markham

California Department ofForestry and Fire Protection

135 RidgewayAve.

Santa Rosa, CA 95401

Re:       THP 1-04-030 SONHansen-Whistler

and associated conversion TCP 04-530

Dear Ms. Markham:

I would like to submit these revised comments on theHansen/Whistler THP and Timberland Conversion THP 1-04-030 SON. The Friends ofthe Gualala River asked me to comment on this project this a few days prior toDecember 20, 2004 deadline. The deadline was subsequently changed to January 7,2005. Therefore, in this letter, I have clarified some issues and reorganizedmy comments for improved readability. I have also added additional references.

The Friends of the Gualala River have asked me to commenton the proposed Negative Declaration for the Hansen-Whistler TimberlandConversion and associated. I was the Hydrologist for the Mendocino County WaterAgency (MCWA) from May 1989 to November 1994. The Mendocino County Board ofSupervisors appointed me as their representative on pre-harvest inspections forTHPs with the potential to impact public water systems. As the MCWAHydrologist, I also reviewed Proof-of-Water pump tests for the Town ofMendocino. I also routinely reviewed CEQA documents for projects before thePlanning Commission. I have a Masters in Physical Science specializing inHydrology from Chico State University. Since 1994 I have been a consultingHydrologist. I have also taught Hydrology at California State University,Monterey Bay.

Timberland Conversion Project

The proposed Hansen-Whistler Timberland conversion islocated in Sonoma County, approximately 1.7 miles northeast of Annapolis. Theproposal is to replace 16 acres of coniferous forest with 14.8 acres ofvineyards and 1.2 acres building site and reservoir. The project is on thenorthwest end of Brushy Ridge. About 14 acres of the proposed conversion drainstowards Little Creek, a tributary of Buckeye Creek. The remaining 2 acres ofthe conversion drain directly towards Buckeye Creek. Buckeye Creek is a Class Istream and is a tributary of the South Fork of the Gualala River. Lower LittleCreek supports steelhead and is therefore a Class I stream. Steelhead werelisted as threatened, in the Northern California ESU, on June 7, 2000. TheGualala River is listed as impaired by sediment and temperature. As a result,the THP associated with the Hansen-Whistler Timberland Conversion must followthe Forest Practice Rule 916.9 Protectionand Restoration in Watersheds with Threatened or Impaired Values.

Based upon my review of the following documents;

·       theMitigated Negative Declaration;

·       theTHP including the Erosion Control Plan

·       Revisionsby the RPF dated August 24, 2004;

·       theHydrology Report by O’Conner dated July 14, 2004

and other documents in the file, I find that the proposedHansen/Whistler THP may cause significant adverse impacts and may result inviolations to subsections of Forest Practice Rule 916.9. I also find that theMitigated Negative Declaration for the Hansen-Whistler Timberland conversion isinappropriate because it is based on an incomplete analysis of the storm-waterrunoff process which ignores the importance of subsurface storm flows inrouting peak flows to the channel network. The potential for erosion from theheadcutting of Class III channels due to increased subsurface storm flows isalso ignored in the THP, Hydrology Report and the Mitigated NegativeDeclaration. In addition, the cumulative effects analysis is very weak and doesnot support the conclusion of no cumulative impacts. Therefore, the CDF shoulddeny the HansenWhistler THP 1-04-030 SON.

Hydrologic Affect of Timberland Conversion Clearcut

The Hansen/Whistler THP and associated Timberlandconversion proposes clearcutting approximately 14 acres in the Little Creekwatershed and about 2 acres in the Buckeye Creek watershed. A clearcut done inassociation with a Timberland Conversion is hydrologically different from aclearcut done in accordance with the standard restocking rules of the ForestPractice Act. The permanent loss of the forest canopy in a TimberlandConversion is central to the hydrologic difference between a TimberlandConversion clearcut and a restocked clearcut. An assessment of the hydrologicimpact of a Timberland Conversion clearcut must consider the permanent loss ofthe forest canopy. 

The hydrologic impacts of a clearcut are related to thefollowing factors;

·       Reductionin evapotranspiration,

·       Lossof canopy interception,

·       Increasesin compaction.

The relative importance of these factors may be differentwhen considering the project’s affect on stream flow during each of threedifferent periods of the year. The three periods of hydrologic interest areearly season storms, later season storms and during the dry season. Thedistinction between early season storms and late season storms can be made onthe basis of the moisture content of the soil column. Early season storms canbe considered those storms that occur when the soil column is relatively dry sothat a portion of the rainfall goes to satisfying the soil moisture deficit.Later season storms are ones that occur after the initial soil moisture deficithas been replenished by the earlier storms. The dry season can be considered tofrom extend from late about April or early May until about mid-November, onaverage.

In a Timberland Conversion, the forest is not replanted.So the surface-area of the forest canopy is never matched by the subsequentleaf area of subsequent uses of the land, which in this case is a vineyard.During most of the rainy season, grape vines are leafless and so the vines donot provide much surface area to intercept rainfall. Thus the amount of rainintercepted and subsequently evaporated back to the atmosphere is permanentlyreduced when a forest in converted to a vineyard. The much smaller surface areaof the leaves of a fully developed vineyard can store only a fraction of therainfall as a +50-year second growth forest. The rainfall stored in thevegetative cover tends to evaporate, especially on a flat ridgetop that iscompletely exposed to the wind and sun, such as this project. So, converting aforest to a vineyard will allow a higher percentage of the rainfall to reachthe ground. Dunne and Leopold (1978, p87-88) summarize research showing thatthe canopy of a coniferous forest intercepts about 22% of rainfall. Most ofthis increase in rainfall reaching the ground must eventually reach the streamchannel network.

A vineyard uses significantly less water than a forest andso soil moisture should be higher at the end of a growing season after theconversion compared to the forest prior to clearcutting. In addition, vineyardsare often irrigated during the summer, which replaces soil moisture with waterfrom a reservoir or with ground water if the irrigation water is supplied by awell.

After a few years, a restocked clearcut’s water use beginsto approximate that of the pre-existing forest. Thus, soil moisture conditionsat the end of the dry season begin to approximate the pre-cut soil moistureconditions. Keppeler (1998) noted that increased summer flows on the South Forkof Caspar Creek lasted only 7 years. The soil moisture regime at the end of thedry season in a Timberland Conversion clearcut will not revert to the pre-cutcondition.

Normal soil processes will tend to decrease the compactionon skid trails over time in a restocked clear cut. But, in a TimberlandConversion clearcut used to grow grapes, a permanent system of roads will beleft between planting blocks. In addition, equipment is often driven down thelanes between rows of vines in a vineyard at various times during the year. Ihave not found studies that address the compaction from equipment use invineyards. But, the gentle slopes and the use of cover crops will probably tendto promote infiltration between rows of vines. However, the permanent roadsbetween vineyard blocks will increase the area subject to overland flow. It isimperative that the vineyard roads be properly designed to quickly drain andprevent the road runoff from concentrating.

The following tablesummarizes the factors that effect streamflow following a clearcut during threeperiods of the year.

Factor Increasing Streamflow	Dry Season Flow	Early Season Storms	Late Season Storms
Reduced Evapotranspiration	Yes	Yes
Reduced Canopy Interception		Yes	Yes

Increased Peak Flows to Little Creek

O’Conner’s July 2004 Hydrologic Assessment analysis ofpeak flows is incomplete. Page 4 of the Hydrologic Assessment states:

The conversion of forestvegetation to vineyard will reduce the interception and evaporation of rainfallby forest canopy. Experimental data indicate that forest canopy intercepts andevaporates approximately 20% of storm precipitation in temperate coniferousforests (Dunne and Leopold 1978, pp. 87-88). Removal of the forest canopytherefore is expected to increase the quantity of precipitation reaching theground surface, potentially causing increases in

Infiltration of water to the soil and percolation to thegroundwater aquifers

Summer streamflow

Storm runoff

The O’Conner report cites studies that suggest that loggingresults in an increase in peak flows but concludes that the gentle slope,distance to the nearest Class III watercourse and surface conditions found onthe Hansen/Whistler conversion site make it unlikely that there will be anincrease in peak flows from the conversion. Page 8 of the O’Conner reportstates that:

Peak flows in stream channels draining this project area mightbe expected to increase, however, several factors suggest that this is unlikelyto occur at this project site. Gentle topography (mean slope within theconversion area is <3%), and the distance between the project area propertyboundary and the nearest stream channel (Class III), suggest that it isunlikely that potential peak flow increases associated with storm runoff willbe effectively routed to the stream channel. Surface storage and roughness withrespect to runoff characteristics between the project site and the Class IIIchannel is relatively high, with irregular topography, substantial surfacestorage capacity and vegetative cover. There is no evidence of continuouschannelized flow draining to the south across or within sight of the projectboundary where most of the potential peak flow increase would be routed.Considered collectively, these facts indicate that stream peak flow increasesobserved at Caspar Creek are unlikely to occur as a result of this project.Consequently, there is little potential for increased channel and bank erosion.Nevertheless, potential peak flow increases are calculated for the project forcomparison with other projects in the area and to establish the maximumpotential flow increase.

O’Conner’s analysis, quoted above, focuses exclusively oninfiltration-excess (Hortonian) overland flow and totally ignores subsurfacestorm flow routing to the channel network. Subsurface storm flow is probablythe dominate pathway in routing runoff from the hillslope to the stream channelnetwork in the forested lands (Church and Eaton 2001) of the Gualala Riverwatershed. Saturated overland flow is probably a locally significant stormwater pathway, for example, the bottom of hillslopes may experience saturatedoverland flow as subsurface flow from upslope raises the water table to thesurface. Areas that tend to remain wet through the summer, such as the wetareas reported along the project property boundary, are another location wheresaturation overland flow will tend to be an important runoff pathway. Incontrast, Hortonian overland flow is probably the least significant pathway (interms of area involved) for storm water to move from the forested hillslopes tothe channel network in the Gualala River watershed during all but the mostextreme storm events. Of course, Hortonian overland flow is the dominatepathway for impermeable surfaces such as roads or compacted skid trails andbedrock. The O’Conner report focuses on the least likely pathway for stormwater to be routed from the project site to the nearby Class III streams duringa 2-year storm. 

Since the project area is on relatively flat ground, it isreasonable to ask if subsurface storm flow would occur on the site. Theproposed Hansen/Whistler timberland conversion project is entirely on Goldridgesoils. The description of the soil sample used to type the Goldridge soilseries as attached. The basic description of the soil is quoted below.

The Goldridge series consists of deep and very deep, moderatelywell drained soils formed in material weathered from weakly consolidatedsandstone. Goldridge soils are on rolling uplands with slopes of 2 to 50percent. The mean annual precipitation is 45 inches and the mean annualtemperature is 56 degrees F.

The Goldridge soil on the project site lies on slopes from2% to 9% and average slope is said to be about 3%. The slope tends to increasewith distance from the crest of the ridge (watershed divide). The Goldridgesoil on the project site was derived from the underlying Ohlson RanchFormation. The O’Conner Hydrology report (2004. p 9) notes that;

The Goldridge soil typically has a subsurface soil stratum withhigher clay content that can impede infiltration

This observation is consistentwith the description of the soil sample used to type the Goldridge soil series.The type sample clay content is shown below.

Horizon	Depth Range	Clay Content
A	0″-24″	10-20%
B	24″-73″	25-35%
C	73″-80″	15-25%

The higher clay content in the Bhorizon indicates that the B horizon has a lower hydraulic conductivity thanthe overlying A Horizon. The O’Conner Hydrology Report shows that the B horizon(subsurface) has a lower infiltration rate (0.2 to 0.63 in/hr) than the surfaceA horizon (0.63-2.0 in/hour), according to the Sonoma County Soil Survey. Thelower infiltration capacity of the B horizon compared to the A horizon is thetypical situation in forest soils (Whipkey and Kirkby, 1978, p127).

The reduced infiltration capacity of the subsurface Bhorizon, due to the higher clay content, provides the very conditions needed topromote subsurface storm flow along the interface of the A and B horizons.There will also be another zone of subsurface flow along the interface betweenthe C horizon and the underlying sandstone of the Ohlson Ranch Formation. Inaddition, groundwater that percolates through the Ohlson Ranch Formation willencounter the nearly impermeable Franciscan Formation and the groundwater willmove downslope along the interface between the Ohlson Ranch Formation and theFranciscan Formation. So, subsurface storm flow will be routed along both theA-B horizon interface and the interface between the C horizon and the OhlsonRanch Formation. In addition, ground water will move downslope along theinterface between the Ohlson Ranch formation and the Franciscan Formation.

The removal of the trees will result in higher antecedentsoil moisture levels, increase subsurface storm flow and a potential increasein percolation to deep groundwater. The increased water moving along thesubsurface storm flow pathways will eventually surface into the drainagenetwork and potentially erode the head of the channel. Jaeger (2004) offers thefollowing summary of the dynamics of channel head formation.

The channel head representsthe start of the drainage network, and its location is influenced by theunderlying bedrock, soil characteristics, climate regime, and land use(Montgomery and Dietrich 1988, 1989; Prosser 1996; Wemple et al. 1996). Pastworkers have proposed that the processes driving channel-initiation and channelhead locations can be mathematically described through exceedence of an erosionthreshold (Dietrich et al. 1992, 1993; Montgomery and Dietrich 1994). Such anerosion threshold is specific to the particular mechanism controllingchannel-initiation (e.g. overland flow, shallow landsliding, and seepageerosion) and is expressed in terms of the contributing drainage area (Acr) and local ground surface slope (q). For example, therequired contributing area required for channel-initiation by overland flow isgiven by

Acr =C/(tanq)a                  (1)

where C is constant as a function of rainfall intensity and site-specificphysical field characteristics (Montgomery and Foufoula-Georgiou 1993). Thesethreshold models predict systematic source area-slope relationships aspresented in Figure 1.

Figure 1. Source area-SlopeRelationship. A Schematic taken from Montgomery and Dietrich (1994) wherelandscape is divided according to dominant channel initiation processes.

Figure 1 (of this letter, presented after the references)shows the proposed Hansen/Whistler timberland conversion superimposed on the1971 Preliminary Geologic Map of Western Sonoma County and NorthwesternmostMarin County, California. The Annapolisportion of the map was drawn on the 7.5’ Annapolis quadrangle from 1943 with25’ contour lines. The superimposed project location is approximate becausedifferences in the base topographic maps make it difficult to overlay thegeologic map on the topographic map showing the project location. The geologicmap shows that, in the project vicinity, Brushy Ridge is underlain by theOhlson Ranch Formation which in turn sits on top of the Franciscan Formation.The Franciscan Formation is much less permeable than the Ohlson Ranch Formationand ground water typically only flows along cracks in the essentiallyimpermeable rock. Therefore, it is likely that a saturated zone develops abovethe Ohlson Ranch/Franciscan boundary. A small portion of the water in theperched saturated zone may leak into fractures in the underlying Franciscan butmost of it will tend to move downslope above the contact and increase the depthof saturation near the head of the Class III channels. The increased depth ofsaturated soil will increase the storm discharge into the channel network. Inaddition to the increased flow along the Ohlson Ranch/Franciscan boundary,there will be increased flow along the A-B horizon interface and increased flowalong the interface between the C horizon and the underlying Ohlson RanchFormation. The increased flow along each of these three subsurface pathwayswill increase the depth of saturation at the contact between the Ohlson RanchFormation and the Franciscan.

In Appendix 2 of the NorthCoast Watershed Assessment Project (NCWAP) Report for the Gualala River Fullerand Custis (2002, p.27) discuss the characteristics of the Ohlson RanchFormation.

The youngest consolidatedgeologic formation in this subdivision is the Ohlson Ranch Formation. Therelatively young marine sediments of this formation are poorly consolidatedsands, silts and gravels that tend to slump or flow when saturated on slopessuch as those near the contact with the underlying Franciscan formation.

So, the increased depth of saturation of the Ohlson RanchFormation at the contact with the Franciscan Formation, after the timberharvest, is expected to cause slumping or earth-flows which will result in theheadward erosion of the Class III watercourses downslope of the project.

Figure 2 shows the approximate location of the OhlsonRanch/Franciscan boundary on a 3-D view of the 7.5 minute topographic map.Figure 2 also shows the likely general direction of the subsurface storm flowand some example hollows (swales) where the increased subsurface storm flow mayhave the potential to initiate headcutting of the channel-head. Headcutting ofthe channel head would cause sediment to enter the channel network and resultin a violation of Forest Practice Rules 916.9(a) (1)(2)(7) which are quotedbelow.

The soils around the Hansen/Whistler Timberland conversionare shown in Figure 3 along with the location of the boundary between theOhlson Ranch Formation and the underlying Franciscan Formation. A profile lineis shown in Figure 3, which may represent a potential flow path from thewatershed divide to the Class III watercourse downslope of the wet area on theproperty line. The elevations along the profile line are shown on Figure 4.Along the profile line, the boundary between the Goldridge and Josephine soilsappear to be located at the boundary between the Ohlson Ranch Formation and theunderlying Franciscan Formation. Both of these interfaces appear to be locatedat the point where Brushy Loop Road crosses the swale. This overlap of thegeologic and soil interfaces may be artificial. The soil maps for the SonomaCounty Soil Survey are known to not align correctly with 7.5-minute topographicmaps. And as noted previously, the 1971 Preliminary Geologic Map also does notline up perfectly with the 7.5-minute topographic map. So, it is possible thatone or both of the geologic and/or soil interfaces occurs at the sharp break inslope at the 720’ contour line shown in Figure 4. This potential error in thelocation of the geologic contact and the boundary of the soils demonstrates theneed to gather field data in the swales upslope of the geologic contact to moreaccurately predict the potential for headcutting of the Class III watercourses.

Dr. Robert Curry (personal communication) reports that hehas observed the following affect of a timberland conversion for a vineyard inNapa County:

After the conversion, old barely-detectable “fossil”swales saturated and developed incipient and then real runoff with overlandflow in what would have been seen as a “zero order” healed in-filledswale.  We didn’t know it was thereuntil after it eroded.

Dr. Curry’s observations verify that headward erosion ofthe channel network does occur after forest clearing for vineyards.

In addition, the increased subsurface storm flow mayincrease the saturated area around the head of the channel leading to increasedsaturated overland flow which would rapidly enter the channel network. Theincrease in saturation near the channel head may also trigger debris-flows inthe steeper channel heads such as those that drain towards Buckeye Creek.Debris-flows are triggered when the drainage out of a mass of colluvium can notkeep pace with the subsurface inflow to the colluvial mass. Typically, thedrainage imbalance is triggered by intense rainfall but the higher soilmoisture induced by the increased subsurface stormflow to the channel head maydecrease the rainfall intensity needed to trigger a debris-flow.

The increased subsurface storm flow would enter thechannel network potentially increasing the storm peaks over pre-harvest levelswhich may in turn induce erosion of the channel bed and banks downstream of thechannel head. This affect is predicted by the O’Conner report (p5), if theincrease in runoff can reach the channel. O’Conner assumes that the runoff can not reach the channel because his analysis only considers Hortonian overland flow and ignores themore likely subsurface storm flow pathway.

The O’Conner report finds that the largest increase in stormrunoff will occur in vineyard block 3 (along the western boundary, the wet areashown in Figure 2 is in block 3). O’Conner predicts a 33% increase or 0.86 cfsin peak storm flow from block 3. Block 5 is adjacent to and south of block 3 ispredicted to have a 21% increase in peak flow or an additional 0.51 cfs. Intotal, the south draining (drains towards Little Creek) conversion areas arepredicted to have a total increase peak flow increase of 14% or 2.06 cfs. Asignificant portion of that flow may be concentrated along the profile lineshown in Figures 3 and 4.

The Caspar Creek study, cited by O’Conner, presentsevidence from a watershed near Fort Bragg, CA that demonstrates that peak flows(storm runoff) are increased by clearcutting. Clearcutting is a required stepin the Timberland Conversion process. Therefore, it is likely that the ClassIII watercourses draining towards Little Creek will experience a significantincrease in peak flows and erosion. The Caspar Creek studies found a mean peakflow increase of 27% for storms with a 2-year recurrence interval on clearcutwatersheds ranging from 25 to 67 acres (O’Conner 2004).

The increases in peak flows predicted by the O’ConnerHydrology Report are in line with the Caspar Creek studies. The flaw in theO’Conner report is that it assumes that the predicted increase in peak flowscan not reach the channel network by overland flow but ignores the subsurfacestorm flow pathways. The O’Conner report (p 11) estimates that an additional 9acre-feet per year might be delivered to the soil each year. The decrease insoil permeability at the A/B horizon interface and at the interface between theC horizon and the underlying Ohlson Ranch formation indicate that subsurfacestorm flows are very likely to occur. The a portion of the subsurface stormflow can be expected to move through soil pipes and macro-pores and so can beexpected to reach the channel network quickly (Church and Eaton, 2001). Some ofthe subsurface storm flow is in the form of saturated flow along the interfacewith layers of lower permeability. Subsurface storm flow can also occur in theunsaturated zone (Montgomery and Dietrich, 2002).

Increased Sediment Discharge to Little Creek

The O’Conner report (p5) summarizes some of the findingsof the Caspar Creek studies regarding increases in sediment load after loggingas follows:

In summary, watershedexperiments at Caspar Creek indicate substantial increases in annual wateryield, summer minimum flows, and storm runoff following clearcut harvest in theNorth Fork Caspar Creek. In addition, suspended sediment yield for small watersheds (about 25 to 70 acres)increased substantially. Increased annual water yield is due largely toincreased storm runoff which results from decreased canopy interception ofrainfall and increased soil moisture; increased summer flows are significant,but represent a smaller portion of the increased annual yield. Increased summerminimum flows result primarily from reduced growing-season evapotranspirationand higher soil moisture. The increasing trend in these parameters andapproximate magnitude of change is likely to be similar conversion of forest tovineyard at the project site near Annapolis. (emphasis added)

In addition, O’Conner reports that:

Lewis (1998) found that suspended sediment yield measured fromthe small watersheds increased on the order of 200% (a three fold increaseafter harvest). Although the source of this increase in suspended sediment wasnot determined, it was suggested that a substantial portion was caused byaccelerated channel or bank erosion associated with observed increases instream flow.

Therefore, the expected increase in the magnitude of peakflows in the Class III watercourses near the Hansen-Whistler TimberlandConversion are also expected to have a significant and measurable increase insuspended sediment load.

The expected increase in peak flow magnitude in thewatercourses near the Conversion results in apparent violations of the threeForest Practice Rules listed below (emphasis added):

916.9(a)(1) Comply with the terms of a Total MaximumDaily Load (TMDL) that has been adopted to address factors that may be affectedby timber operations if a TMDL has been adopted, or not result in any measurablesediment load increase to awatercourse system orlake.

916.9(a)(2) Not result in any measurable decrease inthe stability of a watercourse channel or of a watercourse or lake bank.

916.9(a)(7) Result in no substantial increases inpeak flows or largeflood frequency.

The expected increases in peak flows will violate916.9(a)(7). The expected increase in peak flows from the timberland conversionwill measurably decrease the stability of the bed and banks of upper LittleCreek by initiating headcutting of the channel head, in violation of Rule 916.9(a)(2).The anticipated erosion of the bed and banks of the Class III channels andpossibly the Class I and Class II watercourses downstream in Little Creek willresult in a measurable increase in sediment load in violation of Rule916.9(a)(1).

The expected erosion of the channel-head and the bed andbanks of the Class III watercourses downslope of the Hansen-Whistler TimberlandConversion, as they adjust to the expected increased magnitude of peaks flowdelivered by subsurface storm flow, may result in a direct potential adverseimpact to the steelhead habitat in Little Creek downstream of the Conversion.The steelhead habitat in Little Creek may also be incrementally impacted by thesediment generated from the Hansen-Whistler Timberland Conversion and otherharvests or conversions in the Little Creek watershed. 

Since steelhead, a federally listed species, are known toinhabit the lower reaches of Little Creek, a complete analysis of theenvironmental impacts, including cumulative impacts, of the Hansen/WhistlerTimberland Conversion require analyzing the impact of increased peak flows andthe resulting increase in sediment and other harvests or conversions in theLittle Creek watershed. The Forest Practice Rules quoted above require that theTimberland Conversion not generate and measurable sediment or measurableincreases in peak flows and must not destabilize and channel bed or bank.

The potential adverse environmental impacts from increasedsubsurface storm flow and the resulting increases in peak flow and erosion ofthe Class III channel heads on the steelhead in lower Little Creek invalidatesthe conclusion that the timberland conversion permit for the Hansen-Whistlerconversion project can be issued under the proposed Mitigated NegativeDeclaration. CDF should either deny the application for the Hansen-WhistlerTimberland Conversion or should require an EIR.

Incomplete Project Description

The THP (page 280) claims that there are no Class I, ClassII or Class III watercourses within the plan area. This is not the case. TheTHP states (page 280) that:

No Class I, Class II or Class III watercourses occur withinthe plan area. An off-site Class III watercourse is afforded a minimum 25 footriparian buffer no harvest zone to protect the filter strip vegetation,vegetative cover and habitat.

This statement shows that the Class III watercourse wasgiven a standard WLPZ and treated as part of the plan. The THP goes on to saythat:

A wet area occurs on the property has been avoided andexcluded from the project. It shall be provided an ELZ with a no harvestprescription to protect the filter strip vegetation, vegetative cover andhabitat.

Again, this statement shows that the wet area is a part ofthe plan and that the plan provides specific protections for the wet area andthe surrounding vegetation. The wet area and the Class III watercourse are partof the plan but have been excluded from the cut and provided a certain level ofprotection.

Page 213 of the THP indicates that;

There is a wet area along the property line to the east, forwhich a 150+ foot setback will be maintained. This area has been set aside aspart of a 200 foot wildlife corridor. A small seasonal wet area exists on theproperty line to the south and this area has been set aside along with a fewsurrounding redwood clusters.

The seasonal wet area described as being on the southproperty line is probably the one that has been provided a ELZ and wasdiscussed above. However, while neither of these wet areas will be subjected toharvest activities under the proposed timberland conversion THP, they have notbeen adequately described. These two wet areas may play a crucial role in thesubsurface hydrology of the project site. Since they have not been adequatelydescribed, from a hydrologic perspective, it is not possible to discern theirimportance in understanding the subsurface flow system

The conversion plan does not clearly layout crucialfeatures of the vineyard conversion such as;

·       howmany vines per acre will be planted,

·       howoften the vines will be watered initially or after they have becomeestablished,

·       howmuch water will be applied to each vine per irrigation cycle,

·       howmany irrigation cycles are expected per year

·       howmuch irrigation water will be required during a drought.

Until this information is disclosed, it is not possible toaccurately assess the impact of the proposed project on the local waterresources. It is also important to answer these questions since the economicviability of the proposed vineyard conversion depends on having sufficientwater to establish and maintain the vines.

The watershed area feeding the proposed reservoir alsoneeds to be clearly defined. Calculations need to be shown concerning theamount of rain required to fill the reservoir. Calculations must also be shownregarding how much water the reservoir can expect to receive during a 20-year1-hour storm and how the reservoir spillway will handle the excess flow. Plansmust also be prepared for how to handle the reservoir discharge during a20-year 1-hour rainstorm to prevent the formation of a new channel.

Inadequacy of the Existing Well

Page 37 of the THP is areport by Luciani Pump Company, Inc evaluating the existing well on the HansenWhistler property, dated 9/14/01. The pump evaluation shows that the well produced15.8 GPM and caused 30 feet ofdrawdown after 4 hours and 10 minutes of pumping. The comments on the pumpreport are quoted below.

Comments: The well is plumbed in copper and PVC. It looks likethe homeowner did the work. Electrical is o.k. But has Romex run in PVCconduit.

An estimate for a larger pump is difficult to give at thistime. We need to know the total vines, irrigation block sizes, etc. before apump can be sized. My best guess at this point figuring a 30 GPM pump, pipe,pressure tanks, plumbing, and electrical would be approximately $3,500-$4,000.You should be very careful to not oversize the pump at this point, because wedo not know if the groundwater will change over the years, or what affect thiswell will have on surrounding wells, if any.

This test is for informational purposes only and theconclusions are of the well in its present condition. This test may not showseasonal fluctuations and cannot predict either the future quantity or qualityof water that the well will produce.

This report shows that thepump was tested at 15.8 gpm. Robert Plum of Luciani Pump used an estimate of 30GPM for the purposes of estimating the cost of upgrading the well pump. The 30 GPM estimate is not based on the actual performance of a pump in the well.Mr. Plum states that placing a larger pump in the well could result in thelowering of the groundwater surface or affect neighboring wells.

The THP and the MitigatedNegative Declaration both assume, withoutproof, that the well can produce 35GPM or more. If the well can not consistently supply the assumed amount it ispossible that the vineyard will fail. CDF must require a 72-hour pump testperformed by a qualified hydrogeologist, before approving the MitigatedNegative Declaration. The 72-hour pump test should be conducted in late Augustand be preceded by a 72-hour monitoring period to determine if the water tablesurface is static or declining. Until a 72-hour pump test is performed, thewell should not be regarded as adequate. In fact, the project proponent appearsto have doubts about the ability of the well to supply irrigation water for theproject since some of the land will be used to create a reservoir.

The THP(p 207) and the Mitigated Negative Declaration (p 3-23) both assume that pumpingthe existing well for irrigation water will only impact neighboring wells onlyif the neighboring wells are located close to the pumping well. It is true thatthe cone-of-depression from a pumping well in an unconfined aquifer has a smallradius of influence. However, a well that is pumping from an aquifer of limitedextend, such as the Ohlson Ranch Formation under the northwest end of BrushyRidge, can lower the groundwater table and thereby adversely impact neighboringwells that are much further away that the pumping radius-of-influence wouldsuggest. A properly conducted 72-hour pumping test should be able to determineif extended pumping to irrigate the proposed vineyard might lower the groundwater table.

The THP, the ErosionControl Plan, the Hydrology Assessment and the Mitigated Negative Declarationfail to present any detailed information to support estimates of the amount ofwater required to irrigate the vineyard. Such calculations are essential toassess the environmental impact of the project.

The Mitigated NegativeDeclaration (p3-23) states, without any supporting calculations that theproject will require about 4 acre-feet annually to establish the vines and 2acre-feet per year after the vines are established. Using the planting densityof 2,450 vines per acre given on page 10 of the Timberland Conversion Permitand Application, and a watering rate of 5-gallons per vine per watering cycle,along with the assumption that a total of 12 watering cycles would be required,I estimate that the irrigation requirements for the proposed 14.8 acres ofvineyard is 6.68 acre-feet. This is 167% of the unsupported estimate given inthe plan. This is a crucial calculation and the details need to be revealedbefore the environmental impact can be determined. Also, no information isgiven about the amount of water that would be required during a drought such asthe 6-year dry period from 1987-1992. 

During the drought of1987-1992, the Smith family rainfall records (Table 1), for a site nearAnnapolis, showed annual total ranging from 34.6” to 47”, which is well belowtheir 53.6” average for the 18 years of record. The Independent Coast Observerrainfall records for Annapolis (Table 2) show that the annual totals between1987 and 1992 ranged from 33.7” to 51.7”. The average for 28 years of recordrecorded by the ICO was 59.2”. Both sets of data show that about 34” ofrainfall was the minimum that occurred in the recent drought of 1987-1992.Figures 5 and 6 show the statistics and result of extending the Smith family’srainfall record using the Fort Ross precipitation record. The exceedenceprobability of 34” of rainfall occurring, based on the extended data set (Table3)1, is about 95%, that is only 5% of years would have a lower rainfall.Therefore, the water resources facilities of the proposed vineyard should bedesigned to meet the irrigation needs of a year with only 34 inches ofrainfall.

Much more information isrequired to determine if the existing well can supply the proposed vineyard,especially during the establishment of the vines. FPA Rule 1105.2, quotedbelow, requires that adequate quality and quantity of water be available toensure the economic viability of the project.

1105.2 Director’s Determination

The Director shall determine the applicant’s bona fideintention to convert in light of the present and predicted economic ability ofthe applicant to carry out the proposed conversion; the environmentalfeasibility of the conversion, including, but not limited to, suitability ofsoils, slope, aspect, quality and quantity of water, and micro-climate;adequacy and feasibility of possible measures for mitigation of significationadverse environmental impacts; and other foreseeable factors necessary forsuccessful conversion to the proposed land use.

Dry Season Flow

The Caspar Creek watershed studies suggest that theremoval of trees increases summer streamflow because less moisture is removedfrom soil moisture storage by the replacement vegetation than was used by thetrees. In general this is true but in itself is insufficient to estimate theexpected impacts on the Hansen-Whistler Timberland conversion.

O’Conner Environmental (July 14, 2004) prepared an,Assessment of Potential Hydrologic Effects, Hansen/Whistler Timber Harvest Planand Conversion. The O’Conner report argues that the North Fork of Caspar Creekwas clearcut and therefore would allow reasonable extrapolation of the resultsof the Caspar Creek study to the Hansen/Whistler conversion. Portions of theNorth Fork of Caspar Creek were clearcut and so would, at first glance, appearto be directly applicable to a timberland conversion to vineyard. However, theNorth Fork of Caspar Creek has significant areas of north exposure (higher soilmoisture content than flat or south facing slopes) and there are significantareas with slopes greater than those found on the Hansen-Whistler conversion.The effect of slope, aspect and relative soil water content were not examinedin the Caspar Creek studies. However, the Caspar Creek studies, particularly thoseof the South Fork selective logging offer some insights concerning thevariables that were not directly investigated in the Caspar Creek studies.  

The Keppeler and Ziemer (1990) discuss the factorsassociated with variations in the streamflow response. They note on page 1674that:

High antecedent moisture conditions preceding and during thehydrologic year were related to an increase in the South Fork flow relative tothe North Fork.

This reflects the idea that when the soil is atsaturation, the actual evapotranspiration is close to the potentialevapotranspiration (PET). As soil moisture declines the trees have to reducetheir actual evapotranspiration to levels well below that of the PET. So, theCaspar Creek study supports the idea that the magnitude of any increase insummer streamflow resulting from logging depends on the antecedent soilmoisture conditions. That is, there will be less or no increase in summerstreamflows following dry winters. This is further supported by the followingquote from the 1998 article by E.T. Keppeler discussing the Caspar Creek study.The abbreviation SFC refers to the South Fork of Caspar Creek

On SFC, the minimum discharge (instantaneous daily flow)increased an average of 38 percent or 0.25 L/s/sq-km between 1972 and 1978. Themaximum increase was 0.42 L/s/sq-km in 1973, the final year of timberharvesting on this watershed. No increases were detected in 1977, the driestyear of record. Summer discharge minimumreturned to prelogging levels beginning in 1979. (Emphasis added).

The effect of removing trees on summer streamflow is alsonot uniform in space. The Caspar Creek study can be seen to support the ideathat removing trees from drier sites will have less impact on summer streamflowthan removing trees from wetter sites especially those with nearly saturatedsoil.

Chang (2003, p. 195-199) provides a discussion of thefactors that affect the water yield after timber harvest. The factors discussedby Chang are:

·       Forest-cuttingintensity

·       Species

·       Precipitation

·       Soiltopographic conditions

Chang’s discussion of soil topographic conditions on water yield is quoted below.

Hydrological responses toforest harvests vary among watersheds due to the type and depth of soils alongwith the steepness and orientation of the watershed. Soils of deep and finetextures have a much greater water-holding capacity than soils of shallow andcoarse textures, consequently a greater potential for yield increase. Rowe andReimann (1961) stated that water yield could not be appreciably increased insoils with depth less than about 1 m.

 Slope aspectaffects solar radiation, precipitation and wind speed, consequently soil andair temperatures, snow accumulation, snowmelt, ET, and vegetation type andgrowth. Forest transpiration is generally greater in northern than southernslopes because of denser vegetative cover and deeper soils (Bethlahmy, 1973). Actualobservations showed that clearcutting on south-facing slopes caused only abouta one-third increase of that measured on north-facing slopes in Idaho (Cline et al., 1977) andat Coweeta, North Carolina (Douglas, 1983). (Emphasis added)

Cermak and Kucera (1987) note that;

Transpiration rate decreases under conditions of drought. Thedecrease is proportional to soil water potential, but modified within certainlimits by the physiological properties of plants in the given stands.

The Hansen-Whistler Timberland conversion is on fairlyflat ground or on gentle south facing slopes. The proposed conversion is onGoldridge soil is a well-drained fine sandy-loam. Therefore, both the aspectand the soil type suggest that the conversion will remove trees from relativelydry sites. In contrast, a significant portion of the North Fork of Caspar Creekfaces north and so would be expected to have higher soil moisture content. Inaddition, the clearcuts in the North Fork of Caspar Creek probably removedtrees that were closer to the stream channel network and so grew on sites withelevated soil moisture than the trees that will be removed as part of theHansen-Whistler conversion. So, the actual change in summer streamflow may besignificantly less downstream of the Hansen-Whistler conversion than thechanges seen in the Caspar Creek study.

Studies presented in Dunne and Leopold (pages 253-274)show that areas with saturated or nearly saturated soil moisture conditionstend to be concentrated near the bottom of hillslopes above stream channels.The saturated area tends to contract as the time after precipitation increasesbut the saturated area continues to be centered on the stream channel network.These studies support the idea that the location of tree removal, with respectto topographic position, plays a significant role in determining the responseof the summer low flow to logging.

Furthermore, properly assessing the impacts of thehydrologic changes associated with the timberland conversion should not bebased on “average conditions” but on extremes. During dry years there may be noincrease in summer streamflow associated with the removal of trees during thetimberland conversion.

Inadequate Mitigations

The Mitigated Negative Declaration does not have anyproposed mitigations to deal with the increased storm flow runoff and erosionof the channel-heads in nearby Class III watercourses. The engineering plansfor the reservoir and its outlet works are not given in the plan. Therefore, itdoes not appear that adequate provisions have been made to route storm waterfrom the reservoir spillway to an appropriate channel. Page 3-24 of theMitigated Negative Declaration says that, in case of dam failure, the escapingwater would flow over 150 feet of soils prone to erosion. However, noindication of how normal storm water would be route from the reservoir spillwayto the channel network is given.

Conclusions

The initial study relies on reports that use superficialand incomplete analysis to determine that there would be no significant adverseimpacts to the environment resulting from the Hansen-Whistler Timberlandconversion and associated THP. A careful analysis shows that a variety ofsignificant hydrologic impacts may arise from the Hansen-Whistler Timberlandconversion. These impacts include but are not limited to:

·       Insufficientirrigation water for establishment of the vineyard particularly during dryyears may lead to development of additional water sources with unknownenvironmental impacts or even abandonment of the vineyard.

·       Pumpingthe groundwater within the Ohlson Formation may lower the ground water tableand impact neighbors

·       Subsurfacestorm flow is expected to significantly increase the peak flows in the classIII watercourses that drain to Little Creek.

·       Subsurfacestorm flow and increased percolation to the groundwater table are expected tocause headcutting of the Class II channels and the increased peak flows areexpected to erode the bed and banks of the Class III watercourses downstream ofthe channel head. The resulting additional sediment load may have an adverseimpact on steelhead and their habitat in lower Little Creek.

·       Increasedsaturation of the Ohlson Ranch Formation at its contact with the underlyingFranciscan Formation is expected to result in slumping of the material intoClass III watercourses.

·       Thepotential for significantly increased levels of suspended sediment in the classIII watercourses in upper Little Creek. The resulting additional sediment loadmay have an adverse impact on steelhead in lower Little Creek. The additionalsediment load may also have an adverse effect on the aquatic habitat of upperLittle Creek.

·       Lackof a properly designed channel to route flood water from the reservoir spillwayto the channel network.

The Project Description in the Mitigated Declaration isincomplete and misleading.

Because of these deficiencies in the THP, the ProjectDescription, and inadequacy of the proposed Mitigated Negative Declaration, CDFshould deny the HansenWhistler THP 1-04-030SON.  

Sincerely,

 

DennisJackson

Hydrologist

 

Cc: Allen Robertson, DeputyChief, California Department of Forestry and Fire Protection

 

References

 

 

Blake, M.C. Jr,Judith Terry Smith, Carl Wentworth and Robert H Wright, Preliminary GeologicMap of Western Sonoma County and Northwesternmost Marin County, California. USGS Open-File Report 71-0044, 1971.

Cermak, J. andJ. Kucera, 1987. Transpiration of mature stands of spruce (Picea abies (L.)Karst.) as estimated by the tree-trunk heat balance method. In Forest Hydrology and Watershed Management –Proceedings of the Vancouver Symposium, IAHS, August 1987.

Chang, Mingteh,2003. Forest Hydrology: An Introduction to Water and Forests, CRC Press, New York.

Church,Michael, Brett Eaton, 2001, Hydrological Effects of Forest Harvest in thePacific Northwest Department of Geography, The University of British Columbia, Vancouver,British Columbia, V6T 1Z2 Riparian Decision Tool; Technical Report #3, June,2001

Dunne, T. and L.B. Leopold, 1978. Water inEnvironmental Planning. W.H. Freeman andCompany.

Fuller and Custis, GualalaRiver Watershed Assessment Report. North Coast Watershed Assessment ProgramAppendix 2, Report on the Geologic and Geomorphic Characteristics of theGualala River Watershed, California, by, December 2002, California GeologicalSurvey

Jaeger, Kristin Channel-Initiation andSurface Water Expression in Headwater Streams of Different Lithology. A Master’s thesis University of Washington,2004

Keppeler, E.T.1998. The summer flow and water yield response to timber harvest. PSW-GTR-168,Pacific Southwest Research Station.

Keppeler, E.T.and R.R. Ziemer, 1990. Logging Effects on Streamflow: Water Yield and SummerLow Flows at Caspar Creek in Northwestern California. Water Resources Research,Vol 26, No. 7, pages 1669-1679, July 1990.

Montgomery,David R., William E. Dietrich, 2002, Runoff generation in a steep, soil-mantledlandscape Water Resources Research, VOL. 38, NO. 9, 1168,doi:10.1029/2001WR000822, 2002

O’ConnerEnvironmental, Assessment of Potential Hydrologic Effects, Fairfax TimberHarvest Plan and Conversion Number 1-01-171 SON, Grasshopper Creek andAnnapolis Watersheds, Sonoma County, March 15, 2002

Rantz, S.E. andT.H. Thompson, 1967. Surface-Water Hydrology of California Coastal BasinsBetween San Francisco Bay and Eel River. U.S. Geological Survey Water-SupplyPaper 1851. Prepared in cooperation with the California Department of WaterResources.

Rantz, S.E.1974. Mean Annual Precipitation in the San Francisco Bay Region, California,1931-70. Miscellaneous Field Studies Map MF-613.

Reid, L.M.,1998. Cumulative Watershed Effects: Caspar Creek and Beyond. PSW-GTR-168,Pacific Southwest Research Station.

Soil SurveyStaff, Natural Resources Conservation Service, United States Department ofAgriculture. Official Soil Series Descriptions [Online WWW]. Available URL: http://soils.usda.gov/soils/technical/classification/osd/index.html

Whipkey, R. Z.,and M. J. Kirkby. c1978. Flow Within the Soil. Pages xvi, 389 p. : in M. J.Kirkby, editor. Hillslope hydrology. Wiley,, Chichester ; New York :.

Ziemer, R.R. 1997.Caspar Creek Thornthwaite potential evaporation, water years 1990-1995. U.S.Forest Service, Pacific Southwest Research Station, Redwood SciencesLaboratory, Arcata, CA. See web site:

http://www.rsl.psw.fs.fed.us/projects/water/Thornthwaite.html,

 

 

 

 

 

 

 

Figure 1. The proposed Hansen/Whistlertimberland conversion is shown superimposed on the 1971 Preliminary GeologicMap of Western Sonoma County and Northwesternmost Marin County, California. TheAnnapolis portion of the map was drawn on the 7.5’ Annapolis quadrangle from1943 with 25’ contour lines. The project location is approximate becausedifferences in the base topographic maps makes perfect alignment difficult.

Figure 2. The Hansen/Whistlerconversion (project area is shown as hatched) is on a ridgetop separatingLittle Creek from Buckeye Creek. The top of the ridge is underlain by theOhlson Ranch formation which lays on top of the Franciscan Formation. Removalof the trees on about 14 acres that drain towards Little Creek is expected tocause headcutting of Class III streams upslope of the Ohlson Ranch/Franciscanboundary approximated by the red dashed line in the figure. The short bluedashed lines in the figure show examples of hollows that might experienceheadcutting as a result of the Hansen/Whistler conversion. The wet area shownalong the project boundary near the 840-foot contour line needs to have a morecomplete description in order to determine its role in the hillslope hydrologyof the in an near the project area.

Figure 3. The soils around the Hansen/Whistler Timberland conversion are shownwith the location of the boundary between the Ohlson Ranch Formation and theunderlying Franciscan Formation. The elevations along the profile line areshown on Figure 4. Along the profile line, the boundary between the Goldridgeand Josephine soils appear to be located at the boundary between the OhlsonRanch Formation and the underlying Franciscan Formation.

Figure 4. The elevations along the profile line marked on Figure 3. Thepreliminary geologic map used to derive the location of the OhlsonRanch/Franciscan Boundary line was done on a 25-foot contour line base mapwhich does not perfectly overlay on the 7.5-minute topographic map. Inaddition, the boundaries of the soil units are not precisely located.Therefore, the Ohlson Ranch/Franciscan Boundary and the Goldridge/Josephinesoil boundary may not actually be at the Brushy Loop Road. It is possible thatthe geologic contact and the soil boundary are both located at or near the720-foot contour line where there is a noticeable break-in-slope.

 

 

Figure 5. The upper graph shows the annual rainfall recordedby the Smith family graphed next to the annual Fort Ross precipitation downloadedfrom the California Data Exchange (CDE) web site. The lower graph shows the linearregression of the Annapolis rainfall versus the Fort Ross rainfall.

Table1. The Smith family rainfall data for1984-2001 and the corresponding Fort Ross rainfall data are shown below. Alinear regression performed on the above data found the following equation,Smith Rainfall = 1.419 x (Fort Ross Rainfall) + 2.780 with an R2 =0.9676. The regression is graphed in Figure 3.

 

Year	Fort Ross Annual Precipiation (Inches)	Annapolis Annual Precipitation (inches)		Annapolis vs Fort Ross Regression
1984	38.8	57.91		Intercept	2.780
1985	27.78	41.73		Slope	1.419
1986	47.8	65.87		R-Sq	0.96764
1987	28.4	40.35
1988	29.09	46.14
1989	32.6	47.03
1990	27.74	42.05
1991	22.69	34.64
1992	28.57	45.19
1993	41.39	65.56
1994	23.94	35.89
1995	52.67	85.57
1996	40.5	57.05
1997	36.48	53.97
1998	67.74	96.22
1999	38.8	55.94
2000	35.19	54.86
2001	24.7	38.97

 

 Figure 6. The rainfall recorded by the Smith family wasextended to the period 1906 to 2003 using the regression described in Figure 3.The average for the 98 years of extended record shown is 59.55”. The averagefor the 18 years recorded on Annapolis Drive is 53.61”

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 2. Annapolis rainfall from SteveMcLaughlin of the Independent Coast Observer, PO Box 1200  Gualala, CA 95445 Phone (707) 884-3501;FAX (707) 884-1710.

 

Rainfall Year	Annapolis Rainfall from Independent Coast Observer
70-71	na
71-72	na
72-73	na
73-74	na
74-75	na
75-76	na
76-77	28.13
77-78	84.66
78-79	52.05
79-80	69.66
80-81	49.05
81-82	93.78
82-83	103.04
83-84	63.13
84-85	37.46
85-86	70.36
86-87	39.10
87-88	49.50
88-89	45.90
89-90	51.74
90-91	33.68
91-92	45.42
92-93	61.69
93-94	37.10
94-95	89.39
95-96	58.53
96-97	61.06
97-98	100.78
98-99	57.05
99-00	55.22
00-01	45.95
01-02	52.21
02-03	63.88
03-04	57.05
Years	28
Average	59.16
Median	56.14
Maximum	103.04
Minimum	28.13

Figure 7. Map showing that the averageannual evaporation from water surfaces in the Annapolis area is between 38 and40 inches per year.

Table3. The total annual rainfall (in inches)for various levels of exceedence probability for the Fort Ross data (1906-2003)and for the Annapolis rainfall data extended to the same time period. 95% ofthe years, the rainfall around Annapolis will equal or exceed 34.9”. Theestimated median (50% exceedence probability) rainfall near Annapolis isestimated to be 56.88”. The extended Annapolis average rainfall is 59.55” andis greater than the median (exceedence probability of 41%). The 70” used as theaverage rainfall near Annapolis has an exceedence probability of 23.6%. Thesummary statistics for each rainfall record are shown in the table below theexceedence probability table.

 

Exceedence Probability	Fort Ross Rainfall	Extended Annapolis Rainfall
99%	17.6	27.8
98%	19.4	30.4
95%	22.7	34.9
90%	24.8	38.2
85%	26.2	40.1
80%	28.5	43.0
75%	29.2	44.5
70%	32.3	48.2
65%	34.5	51.2
60%	35.3	52.7
55%	37.0	55.3
50%	38.5	57.1
45%	39.0	58.0
40%	41.4	61.7
35%	42.7	64.1
30%	44.8	65.8
25%	47.2	68.9
20%	48.8	72.0
15%	54.0	82.7
10%	60.5	88.7
5%	66.3	96.9
2%	73.1	106.5
Average	39.98	59.55
Maximum	75.19	109.45
Minimum	16.01	25.49
Median	38.37	56.88
Count	98	98

 

 

 

 

 

 

Table4. The annual runoff/rainfall ratio wascalculated for each year from 1931 to 1970 for the South Fork of the GualalaRiver. Runoff data from Rantz, 1974, runoff map.

Year	South Fork of Gualala River Annual Discharge (1,000 ac-ft)	S. F. Gualala Annual Discharge  (inches)	Fort Ross Water Year Precipitation (inches)	Estimated Watershed Precipitation S.F. Gualala River     (inches)	Runoff Ratio
1931	63.8	7.43	21.82	28.82	25.79%
1932	166.9	19.44	28.7	37.90	51.28%
1933	132.2	15.40	23.64	31.22	49.32%
1934	116.5	13.57	27.38	36.16	37.52%
1935	232.9	27.12	38.52	50.87	53.32%
1936	293.5	34.18	38.9	51.37	66.54%
1937	155.4	18.10	35.06	46.30	39.09%
1938	608.3	70.84	48.39	63.90	110.86%
1939	93.5	10.89	29.18	38.53	28.26%
1940	408.6	47.59	46.63	61.58	77.28%
1941	504.9	58.80	58.99	77.90	75.48%
1942	462.4	53.85	49.56	65.45	82.28%
1943	260.3	30.31	41.64	54.99	55.13%
1944	124.3	14.48	32.66	43.13	33.56%
1945	179.6	20.92	37.37	49.35	42.38%
1946	274.7	31.99	43.85	57.91	55.25%
1947	107.1	12.47	25.05	33.08	37.70%
1948	189.3	22.05	43.02	56.81	38.81%
1949	218	25.39	34.84	46.01	55.18%
1950	142.1	16.55	34.59	45.68	36.23%
1951	341.4	39.76	44.42	58.66	67.78%
1952	434.1	50.56	54.94	72.55	69.68%
1953	342.5	39.89	48.52	64.07	62.25%
1954	341.1	39.72	43.57	57.54	69.04%
1955	171.6	19.98	30.36	40.09	49.85%
1956	464.6	54.11	57.3	75.67	71.50%
1957	222.4	25.90	38.69	51.09	50.69%
1958	560.3	65.25	61.64	81.40	80.16%
1959	178.5	20.79	28.34	37.43	55.55%
1960	224.2	26.11	29.38	38.80	67.30%
1961	270.9	31.55	38.01	50.20	62.85%
1962	266.1	30.99	33.01	43.59	71.09%
1963	307.1	35.76	36.61	48.35	73.98%
1964	138	16.07	26.11	34.48	46.61%
1965	361.5	42.10	38.98	51.48	81.79%
1966	234.5	27.31	35.19	46.47	58.77%
1967	359	41.81	39.3	51.90	80.56%
1968	195.7	22.79	32.22	42.55	53.56%
1969	400	46.58	46.36	61.22	76.09%
1970	407.6	47.47	42.03	55.50	85.52%

LOCATION GOLDRIDGE          CA

Established Series
Rev.DFW/JHR/DJE/ET
02/2003

GOLDRIDGE SERIES

The Goldridge series consists of deep and very deep, moderately well drainedsoils formed in material weathered from weakly consolidated sandstone.Goldridge soils are on rolling uplands with slopes of 2 to 50 percent. The meanannual precipitation is 45 inches and the mean annual temperature is 56 degreesF.

TAXONOMIC CLASS: Fine-loamy, mixed,superactive, isomesic Typic Haplustults

TYPICAL PEDON: Goldridge fine sandyloam–on a south facing slope of 5 percent under apple trees at 350 feetelevation. (Colors are for dry soil unless otherwise stated).

Ap–O to 7 inches; light brownishgray (10YR 6/2) fine sandy loam, yellowish brown (10YR 5/4) moist; singlegrain; soft, very friable, nonsticky and nonplastic; many very fine and fineroots; common very fine and fine tubular and interstitial pores; very stronglyacid (pH 5.0); clear wavy boundary. (4 to 8 inches thick)

A1–7 to 20 inches; light brownishgray (10YR 6/2) fine sandy loam, dark yellowish brown (10YR 4/4) moist;massive; soft, friable, nonsticky and nonplastic; many very fine and fine, fewmedium and coarse roots; many fine and very fine interstitial and tubularpores; strongly acid (pH 5.2); clear wavy boundary. (8 to 15 inches thick)

A2–20 to 24 inches; light brownishgray (2.5Y 6/2) fine sandy loam, yellowish brown (10YR 5/6) moist; massive;slightly hard, friable, nonsticky and nonplastic; common very fine and fineroots; many fine and very fine tubular and interstitial pores; few thin clayfilms in pores; strongly acid (pH 5.1); clear wavy boundary. (2 to 5 inchesthick)

Btl–24 to 28 inches; light gray(10YR 7/2) fine sandy loam, yellowish brown (10YR 5/6) moist; massive; hard,firm, slightly sticky and slightly plastic; many very fine and fine roots; manyfine and very fine interstitial and tubular pores; many thin clay films inpores; very strongly acid (pH 5.0); clear wavy boundary. (3 to 5 inches thick)

Bt2–28 to 41 inches; pale yellow(2.5Y 7/4) sandy clay loam with common fine distinct olive yellow (2.5Y 6/8)mottles, yellowish brown (10YR 5/6) moist with common fine distinct brown(7.5YR 5/4) mottles; massive; very hard, firm, sticky and plastic; common fineand few medium roots; many fine and very fine tubular pores; continuous thickclay films in pores; very strongly acid (pH 4.6); gradual irregular boundary.(10 to 15 inches thick)

Bt3–41 to 57 inches; mottled verypale brown and light yellowish brown (10YR 7/4, 6/4) sandy clay loam, oliveyellow (2.5Y 6/6) moist with common gray (10YR 5/1) streaks; massive, veryhard, firm, slightly sticky and slightly plastic; few fine roots; common fineand very fine tubular pores; continuous thick clay films in pores; extremelyacid (pH 4.3); diffuse wavy boundary. (13 to 18 inches thick)

Bt4–57 to 73 inches; very palebrown (10YR 8/4) sandy clay loam with common fine distinct brownish yellow(10YR 6/8) mottles, yellow (2.5Y 7/6) moist with common coarse prominent gray(10YR 5/1) mottles; massive; hard, firm, nonsticky and slightly plastic; noroots observed; common very fine and fine tubular pores; continuous thick clayfilms in pores; very strongly acid (pH 4.5); diffuse wavy boundary. (0 to 20inches thick)

C1–73 to 80 inches; pale yellow(2.5Y 8/4) fine sandy loam with common fine distinct yellow (2.5Y 7/6) mottles;yellow (2.5Y 7/6) moist with common medium prominent brown (10YR 5/3) mottles;massive, hard, firm, slightly sticky and slightly plastic; no roots observed;common fine and very fine tubular pores; continuous thick clay films in pores;very strongly acid (pH 4.5).

TYPE LOCATION: Sonoma County,California, 2 rows in from Elphic Road in the northeast corner NW 1/4, SW1/4,Section 11, T. 6 M., R. 9 W.

RANGE IN CHARACTERISTICS: The solumis 40 to 60 inches thick. Depth to weakly consolidated sandstone ranges from 40to more than 60 inches. The mean annual soil temperature varies from 53 to 58degrees F. The soil between the depths of 8 to 24 inches is moist in all partsfrom November to May. It is dry in some parts the rest of the year. Reaction isstrongly or very strongly acid throughout.

The A horizon is lOYR 5/2, 5/3, 6/2, 6/3, 2.5Y 5/2, or 6/2. Moist colors arelOYR 4/4, 5/4, 5/6, 6/4, 6/5, 2.5Y 5/4 or 6/4. It is fine sandy loam with 10 to20 percent clay.

The Bt horizon is lOYR 6/2, 6/4, 7/2, 7/4, 2.5Y 6/2, 6/4, 7/2 or 7/4. Moistcolors are lOYR 5/6, 6/6, 7/6, 8/4, 2.5Y 6/6 or 7/6. It is sandy clay loam orclay loam with 25 to 35 percent clay. The upper part of the Bt horizon is finesandy loam in some pedons. Base saturation is 20 to 35 percent.

The C horizon is lOYR 7/2, 7/4, 814, 2.4Y 7/2, 7/4, or 8/4. Moist colors are2.5Y 7/6 or 7/4. It is sandy clay loam or fine sandy loam with 15 to 25 percentclay. Base saturation is 20 to 30 percent.

COMPETING SERIES: These are the Cotati and Sebastopolseries in other families. Cotati soils have thermic soil temperatures.Sebastopol soils are clayey and have a xeric soil moisture regime.

GEOGRAPHIC SETTING: The Goldridgesoils occur on rolling uplands. Slopes are 2 to 50 percent. Elevations rangefrom 200 to 2,000 feet. The climate is subhumid mesothermal with warm drysummers and cool moist winters. Mean annual precipitation varies from 35 to 60inches. Mean annual air temperature is 56 degrees F, mean January temperatureis 45 degrees F, and mean July temperature is 70 degrees F. The frost-freeseason is 225 to 240 days.

GEOGRAPHICALLY ASSOCIATED SOILS:These are the competing Cotati and Sebastopolsoils and the Steinbecksoils. Steinbeck soils have base saturation of 35 to 50 percent in the Bthorizon.

DRAINAGE AND PERMEABILITY:Moderately well drained; medium runoff; moderately slow permeability.

USE AND VEGETATION: Used mostly forapple orchards and timber. Native vegetation consists of redwood, Douglas fir,madrone and tanoak.

DISTRIBUTION AND EXTENT: NorthernCoastal California. The series is moderately extensive.

MLRA OFFICE RESPONSIBLE: Davis,California

SERIES ESTABLISHED: Sonoma County,California, 1915.

REMARKS: This is a classificationchange from fine-loamy, mixed, mesic Typic Haplustults to fine-loamy, mixed,isomesic Typic Haplustults. Change is based on soil-moisture temperature datagathered in adjoining soil survey areas.

The activity class was added to the classification in February of 2003.Competing series were not checked at that time. – ET

This pedon was sampled by the SCS Riverside Soil Survey Laboratory in 1961.Pedon number is S61 Calif 49-6 and is described in the California SSIR No. 24Pages 588 and 589.

Diagnostic horizons and features are as follows:

1. Ochric epipedon – O to 24 inches (Ap, Al, A2); ranges from 14 to 28inches thick. Clay content by Riverside Lab is 9.5 in Ap, 12.2 in Al, and 12.5in A2. Organic matter is 1.48 in Ap, 5.2 in Al and decreases with depth–byRiverside Lab. B.S. is 33 to 38 percent by Riverside Lab.

2. Argillic horizon – 28 to 73 inches (Bt2, Bt3, Bt4); ranges from 23 to 53inches thick. B.S. ranges from 22 to 32 percent by Riverside Lab. The texturalcontrol section is 28 to 48 inches, or the top 20 inches of the argilllic horizon.Clay content by Riverside Lab was 33.4 percent in the Bt2 28.9 percent in theBt3, and 21.6 percent in the Bt4.

3. Mixed mineralogy–U.C. Davis data.

4. Soil temperature 53 to 58 degrees F–based on soil climate transect inMarin and Mendocino Counties on similar soils under similar vegetation.

5. Soil moisture in moisture control section.

J F M A M J J A S O N D

Dry in all parts 7/15-9/15
Moist in all parts 1/1—5/1
Soil is moist in all parts for 214 days and moist in some parts for 300 days.

OSED scanned by SSQA. Last revised by state on 3/87.

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National Cooperative Soil Survey
U.S.A.

 

 

 

 

GOLDRIDGE

 

   Date SC Updated:  18-FEB-03   MO Responsible:  2 (DAVIS, CALIFORNIA)   State Type Location:  CA   Series Status:  E 

   Classification      Subgroup         Soil Order:  ULTISOLS         Suborder:  USTULTS         Great Group:  HAPLUSTULTS         Subgroup Modifier:  TYPIC      Family         Particle Size:  FINE-LOAMY         Particle Size Modifier:           Mineralogy:  MIXED         CEC Activity:  SUPERACTIVE         Reaction:           Soil Temperature:  ISOMESIC         Other:                 

   Series Dates      Origin Year:        Established Year:  1915      Description Date:  02/2003          Date Description Updated:  02/18/2003           

   States Using:  CA  

   MLRAs Using:  14 4B