Understanding the hydrologic impacts of wildfire management strategies using MIKE SHE

Author(s):  
Jake Kurzweil ◽  
Reza Abdi ◽  
Kerry Metlen ◽  
Terri Hogue

<p>Proactive thinning and controlled burning are being utilized to mitigate the effects of severe wildfires across the globe. Hydrologic function of watersheds after wildfire and clear-cutting has been well documented, however the impacts of pre-fire mitigation strategies are less understood. The current study utilized two mixed precipitation watersheds, which supply drinking water for Ashland, Oregon, USA, to assess the effectiveness of restoration and fuel reduction strategies on hydrologic change. This Mediterranean dry mixed conifer-hardwood habitat is unique as it sits in the convergence point of several ecoregions, providing significant biological diversity for the region. Hydrologic response from prior mitigation strategies was evaluated using max monthly flow, mean annual 7-day low flow, runoff ratios, timing and total water yield. Results show an average decrease of 26% and 24% in total annual water yields in the West and East basins of the Ashland watershed, respectively. Analysis also showed that 66% (West) and 72% (East) of the changes in water yield were due to annual variations in precipitation, demonstrating that land cover changes were not the dominant driver of hydrologic change. Current work includes identifying the thresholds at which stand density reduction leads to an increase in annual surface water yield. The integrated surface and groundwater model, MIKE SHE, is developed and used to simulate a range of forest fire mitigation efforts based upon representative parameters in the model, including leaf area index. Findings will then be expanded to include stand density index for better interpretation of our findings to make recommendations for local and regional forest managers. Ultimately, results will help inform future implementation of forest restoration and climate adaptation at larger scales.</p>

2002 ◽  
Vol 78 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Victor J Lieffers ◽  
Bradley D Pinno ◽  
Kenneth J Stadt

This study examines light competition between aspen and spruce during the sequence of aspen development. Leaf area index and light transmission were measured or estimated for aspen stands from 2 to 125 years old. Light transmission was lowest at 15-25 years, and in some stands, transmission was less than 5% of above-canopy light. Hypothetical aspen stands with various stem configurations and heights were developed, and positions were identified that would meet or fail Alberta free-to-grow (FTG) standards. Light transmission was estimated at each position with the MIXLIGHT forest light simulator. Positions in canopy gaps or at the northern sides of canopy gaps had higher light. In general, however, there was little difference in available light between positions that met or failed FTG criteria. Stand density and size of aspen trees appears to be a better index to predict light transmission and spruce success in juvenile aspen stands than current FTG criteria. Key words: competition, free to grow, hardwood, spruce, light


Author(s):  
Md. Sanaul H. Mondal ◽  
Md. Serajul Islam

Bangladesh shares a common border with India in the west, north and east and with Myanmar in the southeast. These borders cut across 57 rivers that discharge through Bangladesh into the Bay of Bengal in the south. The upstream courses of these rivers traverse India, China, Nepal and Bhutan. Transboundary flows are the important sources of water resources in Bangladesh. Among the 57 transboundary rivers, the Teesta is the fourth major river in Bangladesh after the Ganges, the Brahmaputra and the Meghna and Bangladesh occupies about 2071 km2 . The Teesta River floodplain in Bangladesh accounts for 14% of the total cropped area and 9.15 million people of the country. The objective of this study was to investigate trends in both maximum and minimum water flow at Kaunia and Dalia stations for the Teesta River and the coping strategies developed by the communities to adjust with uncertain flood situations. The flow characteristics of the Teesta were analysed by calculating monthly maximum and minimum water levels and discharges from 1985 to 2006. Discharge of the Teesta over the last 22 years has been decreasing. Extreme low-flow conditions were likely to occur more frequently after the implementation of the Gozoldoba Barrage by India. However, a very sharp decrease in peak flows was also observed albeit unexpected high discharge in 1988, 1989, 1991, 1997, 1999 and 2004 with some in between April and October. Onrush of water causes frequent flash floods, whereas decreasing flow leaves the areas dependent on the Teesta vulnerable to droughts. Both these extreme situations had a negative impact on the lives and livelihoods of people dependent on the Teesta. Over the years, people have developed several risk mitigation strategies to adjust with both natural and anthropogenic flood situations. This article proposed the concept of ‘MAXIN (maximum and minimum) flows’ for river water justice for riparian land.


1996 ◽  
Vol 21 (1) ◽  
pp. 241-241
Author(s):  
Gene Burris ◽  
Don Cook ◽  
B. R. Leonard ◽  
J. B. Graves ◽  
J. Pankey

Abstract The test was conducted at the Northeast Research Station in St. Joseph, LA. Plots were replicated 4 times in a RCB design and were four rows (40-inch spacing) X 65 ft. ‘Stoneville LA 887’ cotton seed was planted 2 and 3 May on a commerce silt soil which was fertilized sidedress with 90 lb N/acre. Cotton seed were planted with a John Deere model 7100 series planter which was equipped with 10 inch seed cones mounted to replace the seed hoppers. The seed rate was 4 seed/row ft. Granular in-furrow treatments were applied with 8 inch belt cone applicators mounted to replace the standard granular applicators. Control of thrips and aphids was evaluated on 5 randomly selected plants/plot. Evaluations were made on 18, 19, 24, 26, and 29 May and 8 Jun. Plant height counts were taken on 10 randomly selected plants/plot on 8 Jun. Stand density and leaf area was determined by counting the number of plants in a randomly selected meter on 29 May. Leaf area was recorded using a Li Cor leaf area machine. The data was recorded as cm2 and converted to a leaf area index (LAI). Major pests and/or secondary pest control was initiated in Jun and continued on an “as needed” basis through Aug.


1993 ◽  
Vol 23 (12) ◽  
pp. 2521-2536 ◽  
Author(s):  
Xiwei Yin ◽  
Paul A. Arp

A process-oriented forest soil temperature model, FORSTEM, is presented. FORSTEM considers vertical heat conduction as well as freezing and thawing, and it lumps the effects of forest canopies on soil surface temperature with the surface heat transfer coefficient. It runs in conjunction with the forest hydrologic model, FORHYM. FORSTEM and FORHYM input is limited to (i) air temperature; (ii) precipitation and its snow fraction; and (iii) descriptive site information (latitude, elevation, slope, aspect, forest coverage, and soil layer thickness and texture). FORSTEM uses generalized parameters derived from existing empirical information. The model was applied to 10 different cover type–site conditions, including lawns, deciduous forests, and coniferous forests before and after clear-cutting in Ontario, Quebec, New Brunswick, and Colorado. The only model parameter we calibrated for different sites was the effective ground/air conductance ratio. The ratio was found to be a function of incoming solar radiation and vegetative area index. Differences between monthly simulations and field measurements fell within ± 1.5 °C for at least about three-quarters of the data cases at individual sites. Major exceptions occurred when temperature measurements showed no damping down the soil profile or with soils containing large air gaps between coarse rock fragments.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Siti Aisah Shamsuddin ◽  
Zulkifli Yusop ◽  
Shoji Noguchi

A study was conducted on the impact of forest clearance on discharge from newly established Hopea odorata plantations catchment (14.4 ha). The stands were two years old when this study commenced in year 2006 and the data collection was carried out for two years. The forested catchment (C3) was clear-cut during the preparation of the forest plantation and catchment C1 was left undisturbed. Discharge and rainfall were measured continuously for two years. The discharge measured from years 1997 to 2003 was used also to determine the water yield before and after forest clear-cut. This study showed that the plantation catchment is more responsive to storm with higher total water yield than in the forested catchment. The effect of forest clear cutting to discharge was clearly shown by the increment in the amount following the clear-cut activities and time taken for the recovery of the discharge back to its original state was almost three years. The peak discharge in C3 also was affected in which the biggest change was obtained during the forest clear-cutting period compared with during calibration and after clearing periods. This study is useful as basis for improving the existing guidelines on forest plantation establishment.


2021 ◽  
Author(s):  
Moctar Dembélé ◽  
Mathieu Vrac ◽  
Natalie Ceperley ◽  
Sander J. Zwart ◽  
Josh Larsen ◽  
...  

Abstract. A comprehensive evaluation of the impacts of climate change on water resources of the West Africa Volta River basin is conducted in this study, as the region is expected to be hardest hit by global warming. A large ensemble of twelve general circulation models (GCM) from CMIP5 that are dynamically downscaled by five regional climate models (RCM) from CORDEX-Africa is used. In total, 43 RCM-GCM combinations are considered under three representative concentration pathways (RCP2.6, RCP4.5 and RCP8.5). The reliability of each of the climate datasets is first evaluated with satellite and reanalysis reference datasets. Subsequently, the Rank Resampling for Distributions and Dependences (R2D2) multivariate bias correction method is applied to the climate datasets. The corrected simulations are then used as input to the fully distributed mesoscale Hydrologic Model (mHM) for hydrological projections over the twenty-first century (1991–2100). Results reveal contrasting changes in the seasonality of rainfall depending on the selected greenhouse gas emission scenarios and the future projection periods. Although air temperature and potential evaporation increase under all RCPs, an increase in the magnitude of all hydrological variables (actual evaporation, total runoff, groundwater recharge, soil moisture and terrestrial water storage) is only projected under RCP8.5. High and low flow analysis suggests an increased flood risk under RCP8.5, particularly in the Black Volta, while hydrological droughts would be recurrent under RCP2.6 and RCP4.5, particularly in the White Volta. Disparities are observed in the spatial patterns of hydroclimatic variables across climatic zones, with higher warming in the Sahelian zone. Therefore, climate change would have severe implications for future water availability with concerns for rain-fed agriculture, thereby weakening the water-energy-food security nexus and amplifying the vulnerability of the local population. The variability between climate models highlights uncertainties in the projections and indicates a need to better represent complex climate features in regional models. These findings could serve as a guideline for both the scientific community to improve climate change projections and for decision makers to elaborate adaptation and mitigation strategies to cope with the consequences of climate change and strengthen regional socio-economic development.


2018 ◽  
Vol 48 (11) ◽  
pp. 1388-1397 ◽  
Author(s):  
Xiongqing Zhang ◽  
Lele Lu ◽  
Quang V. Cao ◽  
Aiguo Duan ◽  
Jianguo Zhang

The self-thinning rule is fundamental in regulating maximum stocking and constructing stand density management diagrams. Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) is the most important tree species and widely distributed across subtropical China. Yet, our understanding of how the self-thinning line of Chinese fir relates to climate is limited. Longitudinal data from 48 plots distributed in Fujian, Jiangxi, Guangxi, and Sichuan provinces were used to describe self-thinning for Chinese fir in relation to climate through first-order autoregressive (AR(1)) and nonlinear mixed effects (NLME) models. Results showed that self-thinning lines had steeper slopes for Chinese fir growing in areas with larger annual precipitation and summer mean maximum temperature but flatter slopes with higher mean annual temperature, degree-days below 0 °C, and winter mean minimum temperature. Winter mean minimum temperature was the dominant climatic factor in shaping self-thinning lines, which suggests that temperature was the key climate driver that affects self-thinning of Chinese fir. In addition, differences of slopes for any two of the four sites were significant, except between the Guangxi and Sichuan sites. Our results will be useful for both the silvicultural practices and mitigation strategies of Chinese fir under climate change in south China.


2018 ◽  
Vol 22 (3) ◽  
pp. 1749-1766 ◽  
Author(s):  
Yuan Zhang ◽  
Xiaoming Feng ◽  
Xiaofeng Wang ◽  
Bojie Fu

Abstract. The frequency and intensity of drought are increasing dramatically with global warming. However, few studies have characterized drought in terms of its impacts on ecosystem services, the mechanisms through which ecosystems support life. As a result, little is known about the implications of increased drought for resource management. This case study characterizes drought by linking climate anomalies with changes in the precipitation–runoff relationship (PRR) on the Loess Plateau of China, a water-limited region where ongoing revegetation makes drought a major concern. We analyzed drought events with drought durations ≥ 5 years and mean annual precipitation anomaly (PA) values ≤ −5 % during drought periods. The results show that continuous precipitation shifts are able to change the water balance of watersheds in water-limited areas, and multi-year drought events cause the PRR to change with a significantly decreasing trend (p < 0.05) compared to other historical records. For the Loess Plateau as a whole, the average runoff ratio decreased from 10 to 6.8  % during 1991–1999. The joint probability and return period gradually increase with increasing of drought duration and severity. The ecosystem service of water yield is easily affected by drought events with durations equal to or greater than 6 years and drought severity values equal to or greater than 0.55 (precipitation ≤ 212 mm). At the same time, multi-year drought events also lead to significant changes in the leaf area index (LAI). Such studies are essential for ecosystem management in water-limited areas.


1991 ◽  
Vol 21 (3) ◽  
pp. 300-305 ◽  
Author(s):  
N. J. Smith

Salal (Gaultheriashallon Pursh) leaf biomass, leaf area index, specific leaf area, and leaf morphology were examined in 13 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands from 37 destructively measured 1-m2 quadrats. In response to light and stand overstory density, salal shoots produced either mainly sun leaves or mainly shade leaves. Sun leaves were associated with sunflecks in open-grown or variably stocked stands. Shade leaves were associated with diffuse light under denser stands. Sun-leaf quadrats had mean specific leaf areas less than 90 cm2/g; shade-leaf quadrats had mean specific leaf areas greater than 90 cm2/g. Sun leaves were narrower, with average leaf widths less than 5 cm. Quadrat salal leaf biomass and leaf area index peaked at Curtis' metric relative density 5.9, which corresponded to an availability of 15% of global photosynthetically active radiation. Sun-leaf quadrats occurred below relative density 5; shade-leaf quadrats occurred above relative density 4. A mixture of sun- and shade-leaf quadrats occurred between about relative density 4 and 5, depending on the uniformity of stocking.


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