FutureWater, in collaboration with TUDelft and the TWIGA project, has participated in the Precipitation and Urban Hydrology session of the European Geosciences Union (EGU) conference which is held from 4-8 May. In response the ongoing coronavirus pandemic the EGU has gone completely virtual and hosted the EGU2020: Sharing Geoscience Online. This event will offer all geoscientists opportunities to share their research and stimulate scientific discourse during these unprecedented times.  During the session the added value of flying sensors (drones or UAVs) for urban hydrology and flood mapping was highlighted: it is a very effective means to map riverbeds and flood extent accurately across a wide area, even while the flood is happening or shortly thereafter. Flood mapping information is also very valuable in a long-term context, for drainage infrastructure planning and management.

The promises and challenges of deploying flying sensors for the purpose of urban hydrological modelling and flood mapping were discussed. This was illustrated a case-study in Kumasi, the second biggest and fastest growing city in Ghana, where urban flooding has become more frequent due to changes in the climate and have a more negative impact due to rapid urbanization and population growth. Not only are the natural flood plains increasingly being used for anthropogenic purposes, the increased population growth also brings along more solid (plastic) waste on the streets and into the riverbeds and riverways. This creates blockages in drains and riverways, which reduces its drainage capacity and adds to the flooding problems. Flying sensors were used to collect elevation information (DEM), riverbed dimensions and land-use. This information was used to construct a hydrological model to predict river flows and flooding.

Example applications of UAV imagery for flood mapping
Example applications of UAV imagery for flood mapping presented at the EGU.

Myanmar is a country with huge water and agriculture-related challenges. However, ground data on e.g. river flows, rainfall and crop growth are only very sparsely available. This training supported by Nuffic aimed to build capacity across the water sector in Myanmar in overcoming these limitations by using Google Earth Engine, a state-of-the art tool for accessing and processing a wealth of geographical datasets. Participants from academia, higher education, and govenment agencies, attended two training sessions hosted by YTU (the main requesting organization) and implemented by FutureWater and HKV. During the intermediate period, remote support was offered to the participants via Skype, email and the dedicated Facebook page. Results of the individual assignments, which were formulated by the participants based on their personal objectives, were presented in a final symposium.

Higher educational staff was trained to achieve sustainable impact by implementing Google Earth Engine in their curricula and train a new generation of modern and well-equipped water professionals. Public sector representatives participated to obtain skills that can be directly and sustainably implemented in their respective organizations, to benefit effective and equitable water management.

The North–South Corridor serves as the main transport artery for the region, which spans quite diverse and spectacular terrains from the historic capital of Georgia, Mtskheta, up north to Stepantsminda in the Great Caucasus mountain range. The road experiences heavy traffic and is unsafe due to a design that is inadequate for the challenging geographical and climatic conditions, particularly in winter. The area is prone to avalanche, landslide, and snow load risks, which cause frequent and extended closures of the road. The two-lane highway provides a low standard alignment and is characterized by substandard open tunnels and avalanche galleries, in which modern trucks cannot pass simultaneously. An upgrade of the existing road alignment with improved geometry and avalanche galleries was considered but deemed inappropriate as it would not address the core climate-related risks.

Recognizing these challenges, the government has therefore requested ADB’s and EBRD’s assistance to improve the North–South Corridor. The climate-resilient project road will allow more traffic to travel on it safely and will remain fully operational all year. A detailed Climate Risk and Vulnerability Assessment (CRVA) report has been developed for the project road. The projected increase in extreme precipitation events is considered as the most important climate risk for the project road. This not only leads to higher extreme discharges, but can also lead to more frequent landslides, mudflows, and avalanches. The climate model analysis yields following conclusions for the project area:

  • Temperature increases by about 2 °C (RCP4.5) to 2.7 °C (RCP8.5) are to be expected
  • Minimum and maximum temperature are likely to change inconsistently, with maximum air temperatures increasing more than minimum air temperatures. This implies a larger diurnal temperature range for the future
  • Extremes related to temperatures (e.g. warm spells, extremely warm days) are likely to increase in frequency and intensity
  • Precipitation totals are likely to stay reasonable constant
  • Precipitation extremes are likely to increase in frequency and intensity. Maximum 1-day precipitation volumes with return periods of 25, 50 and 100 years are expected to increase by about 10% to 20%.

Stress tests were carried out by the project road design consultant team using +10% and +20% increased precipitation input for return periods used in the engineering design. These tests revealed that bridges have sufficient capacity in the current design to cope with higher discharge levels in the future, although it would be prudent to check the bridge substructure designs for higher flow velocities and the possibility of increased debris content in the flow. The tests indicated that a small proportion of the transversal and longitudinal drainage systems might have insufficient capacity to cope with the increased precipitation extremes. These should be identified, and their dimensions increased appropriately.

Due to its geographic location, Georgia’s role as a major transit country is significant. Transport of goods into and through Georgia has increased over the past 10-15 years. Almost two-thirds of goods in Georgia are transported by road but the roads are poorly equipped to cope with the volume of traffic and the proportion of heavy vehicles, and factors such as insufficient dual carriageways, routing through inhabited areas and inadequate maintenance and repair, hinder throughputs and increase transit times. The government of Georgia has therefore launched a program to upgrade the major roads of the country, including part of the East-West (E60) Highway. This climate risk and vulnerability assessment (CRVA) has examined the proposed components for section Shorapani-Argveta (F4) of the East-West Highway Road Project. The climate model analysis yields following conclusions:

  • Temperature increases by about 2.1 °C (RCP4.5) to 2.9 °C (RCP8.5) are to be expected
  • Minimum and maximum temperature are likely to change inconsistently, with maximum air temperatures increasing more than minimum air temperatures. This implies a larger diurnal temperature range for the future
  • Extremes related to temperatures (e.g. warm spells, extremely warm days) are likely to increase in frequency and intensity
  • Precipitation totals are likely to stay reasonable constant
  • Precipitation extremes are likely to increase in frequency and intensity. Maximum 1-day precipitation volumes with return periods of 25, 50 and 100 years are expected to increase by about 10% to 20%.

The increase in extreme precipitation events is considered as the most important climate risk for the project road. This may lead to higher extreme discharges that exceed the systems’ design capacity and cause flooding or inundation of road infrastructure. More extreme precipitation events can also lead to increased slope instability alongside the project road, causing more frequent and more powerful landslides, rockfalls and/or avalanches. In addition, the projected increase in diurnal temperature variability may lead to an increase in freeze–thaw conditions. This may result in deterioration of road pavement integrity, resulting in more frequent maintenance requirements. It can also further increase the risk of slope instability, making any stretch of road close to steep terrain more vulnerable to such mass movement phenomena.

According to the design team, the structures at risk of flooding (e.g. bridges, road sections) are sufficiently dimensioned to cope with return levels 10-20% higher than used in the original design calculations, which can be reasonably assumed. Retaining walls and mass movement protection structures are in place. The performance and sustainability of the pavement structure and structural joints may be adversely affected by the increase in the diurnal temperature range. To mitigate this risk, it advised to use road pavement with highest capability.

ADB is providing a technical assistance grant to the government of Tajikistan (the government) for the preparation of the CAREC corridors 2, 3, and 5 (Obigarm–Nurobod) Road Project. The project road, about 72 km long, will replace a section of the existing M41 highway that will be inundated due to the construction of the Rogun Hydropower (HPP) project. The project road passes through mountainous terrain and includes 3 tunnels of total length about 6 km, several substantial bridges, and a high level 700 m long bridge over the future hydropower reservoir. The bypass road must be completed and opened to traffic by latest November 2023, the date by which the rising water in the HPP reservoir will have inundated several critical sections of the M41 highway. No other part of Tajikistan’s national highway network can provide for this traffic, and the only alternative route would represent a deviation of about 500 km.

The executing agency for implementing the project is the Ministry of Transport (MOT), represented by its Project Implementation Unit for Roads Rehabilitation (PIURR). The detailed design of the road has been completed by a national design consultant appointed by Tajikitan’s Ministry of Transport (MOT). This climate risk and vulnerability assessment (CRVA) has examined the proposed components for CAREC corridors 2, 3, and 5. A detailed climate risk assessment was conducted for the project road for the period to 2050 to ensure the design specifications are adequate for future climatic conditions. The climate model analysis yields following conclusions:

  • Temperature increases by about 2.4 °C (RCP4.5) to 3.1 °C (RCP8.5) are to be expected.
  • Minimum and maximum temperature are likely to change inconsistently, with maximum air temperatures increasing more than minimum air temperatures.
  • Extremes related to temperatures (e.g. warm spells, extremely warm days) are likely to increase in frequency and intensity.
  • Precipitation totals are likely to increase slightly but a large spread in precipitation projections has to be noted.
  • Precipitation extremes are likely to increase in frequency and intensity. For example, maximum 1-day precipitation volumes with return periods of 50 and 100 years are expected to increase by about 20% according to the 75th percentile values in the distribution of change projections of the entire climate model ensemble.

The increase in extreme precipitation events is considered as the most important climate risk for the project road. This not only leads to higher extreme discharge events but can also lead to more frequent and more powerful mudflows, landslides, and/or avalanches. The increase in temperature can pose additional loadings from thermal expansion to bridge joints and bearings as well as the road pavement asphalt, but it is unlikely that these would be significant.

The project design consultant team recalculated the expected flow characteristics for bridge sections for 1:100 years discharge events using a foreseen 20% increase in daily maximum precipitation. The recalculations reveal that bridges have sufficient capacity in the current design to cope with higher discharge levels in the future, although it would be prudent to check the bridge substructure designs to withstand higher flow velocities and increased debris content in the flow. Heavier scour protection works may be required if structural deterioration of bridge components is observed. The project design consultant team similarly recalculated the expected flow characteristics for culvert and roadside drains, but now for 1:50 years discharge events considering a 20% precipitation increase. The recalculations reveal that the drainage capacity of the culverts is well in excess of foreseen increases in flow, whether it be precipitation, mudflow, or avalanche.

The Asian Development Bank (ADB) is committed to supporting the Uzbekistan Government’s integrated rural economic development initiative that can revitalize the rural economy and help build modern infrastructure and government services in the rural areas. ADB has included targeted programs to provide modern and highly efficient rural infrastructure for power distribution. On these projects, ADB will support the Government’s initiative by means of a result-based lending (RBL) program. One of the key envisioned outputs of the program is to modernize and augment the electricity distribution system. The goal is to start in three provinces: Bukhara, Samarkand and Jizzakh. The proposed project will help Uzbekistan address high technical losses in the power distribution system and improve the electricity supply reliability in the remote areas.

Electricity Transmission and Distribution (T&D) projects are sensitive to climate conditions. Temperature, wind and other variables are typically integrated and considered in the design, as also for this particular project. Thus, changes in these variables due to climate change may affect the performance of the system. Based on these sensitivities, an analysis of climate change projections in the project area (three provinces) was performed, focusing on climate means & extremes (temperature and rainfall) and wind speed trends based on reanalysis (historic) datasets. Overall, the climate model analysis yields following conclusions for the project area:

  • Temperature increases by about 2.1 °C (RCP4.5) to 2.7 °C (RCP8.5) are to be expected.
  • Extremes related to temperatures (e.g. warm spells, extremely warm days) are likely to increase in frequency and intensity.
  • Precipitation totals are likely to stay reasonably constant but the GCMs show a large range of uncertainty under both the RCP 4.5 and RCP 8.5
  • Precipitation extremes are likely to increase in frequency and intensity. Maximum 1-day precipitation volumes are expected to increase by about 15% and dry spells are expected to last longer.

Historic trends of wind speed were analyzed for Uzbekistan based on reanalysis data. Based on data over more than a century the data suggests that higher wind speeds (more frequent and/or more intense storms) can be expected in the future.

Considering the type of climate hazards and risks in the project area, and the area-specific climate change projections, overall the most serious threat comes from the expected increase in temperature extremes. Heat related stresses may put significant strain on the electricity system, leading to system faults, reduced power supply and power outages. Dust storms may also occur more frequently due to increased drought conditions, causing transmission losses to overhead power lines and damage transformers and distribution substations. In addition, while the hazard exposure is constricted to smaller parts of the project area, the expected increase in extreme precipitation events may lead to more frequent and powerful flooding events. Flooding and inundation of electricity network infrastructure have major impacts, often causing partial or complete power outages. Higher extreme discharges can also lead to more frequent landslides and more powerful mudflows, posing serious risk of damaging transmission towers which may lead to power outages.

 

There is great potential for hydropower in Georgia, and this natural resource is likely to be increasingly utilised for power generation in the future. With the escalating demand for energy, government authorities are keen to harness renewable energy from the country’s main rivers. Often these projects aim at remote communities for which connecting to the national power grid is expensive. Hence, local hydropower production is an attractive and sometimes viable option. Critical is to conduct accurate feasibility assessments for hydropower generation at the different potential sites of interest considering climate change impacts. This work is a glacio-hydrological assessment of the expected river discharge at the planned hydropower sites in the Mestiachala river, Georgia.

Based on the requirements of the project, the Spatial Processes in Hydrology (SPHY) cryospheric-hydrological model was selected for the assignment. SPHY is a hydrological model that simulates the runoff at any location within the basin at a daily timescale. SHPY is ideal to assess glacier and snow influence in the river discharge and evaluate the impact of climate change. SPHY was used to predict the river discharge for the extended period of record and provide enhanced flow duration curves for hydropower assessment. In addition, total runoff components were quantified such as snow and glacier runoff.

This glacio-hydrological assessment delivered river discharge estimates for intake locations of two planned runoff river hydropower plants near Mestia, Georgia. The assessment included the calibration of a hydrological model, daily river discharge simulation for an extended period of record (1980-2015), climate change scenarios, and the derived flow duration curves to evaluate the flow operation of hydropower turbines. In addition, total runoff components were quantified such as snow and glacier runoff.

The daily river discharge was simulated at the two intake locations for two future periods (for the end of the concession period and for the end of century period) considering two climate change scenarios (RCP4.5 and RCP8.5). Hydrological model simulations were developed using future precipitation and temperature predictions and future glacier extent predictions. The climate change scenarios provide an evaluation of flow operation uncertainty. The daily flow calculations for the two sites can be used in the hydropower calculations, and to assess the overall profitability of the planned investment, taking into account energy prices, demand, etc.

From 4 till 15 November, FutureWater and HKV gave a hands-on training at Yangon Technological University on using the Google Earth Engine cloud computing platform for satellite-derived data analyses for water resources management in Myanmar. The 8-day training was organized under the framework of the Orange Knowledge Tailor-Made Training (TMT) Program, which is funded by NUFFIC, the Dutch organization for internationalization in education. The training in November will be followed up by a final 5-day course from 9-13 December, where participants will finalize individual assignments and present their work during a symposium. Communication experts from the Water Agency have been closely involved in this aspect of the training. The participants, which include policy makers, researchers and the private sector are expected to gain a more advanced skillset of processing and analyzing remote sensing data in Myanmar, which can help enhance the water resources sector in Myanmar.

Brainstorm session on individual assignments.

During the last week of August, FutureWater and HiView joined TU Delft and local partners for a scientific field campaign at Nyankpale-Tamale in the northern part of Ghana. This was possible as part of the Horizon 2020 project TWIGA, Transforming Weather Water data into value-added Information services for sustainable Growth in Africa. Hosted by the Savanna Agriculture Research Institute (SARI), a 1000 m long Distributed Temperature Sensing (DTS) cable has been installed at an agricultural field at 5 and 10 cm depths. The DTS measurements provide a temperature profile across the field which can be used to derive soil moisture and can be related to drought and estimates for evaporation. A Trans-African HydroMeteorological Observatory (TAHMO) weather station has also been installed in the field and is continuously collecting weather information and data on soil moisture and soil temperature.

The DTS cable will be kept in the soil for over two years and measurement will take place at the start and end of the rainy seasons. The overall objective is to help improve satellite-derived weather forecasting products (which are often too unreliable around the equator) that can support smallholder farmers in their farm management decisions. FutureWater and HiView contributed to the field campaign by making numerous flights with a flying sensor (UAV) equipped with a thermal camera. The flying sensor and DTS temperature data will be compared with each other and with temperature data captured by satellite imagery, and will serve as high-resolution input for energy balance algorithms to estimate evapotranspiration at field scale.

The ‘headquarters’ of the DTS field campaign at Nyankpale-Tamale, Ghana.
Jan van Til from HiView taking thermal images with a flying sensor.

In November 2018, just after the TWIGA days in Kumasi, Ghana, FutureWater, together with partners Hiview and Farmerline, conducted a pilot study using flying sensors (drones) to enhance irrigation water productivity and yields of pineapple farmers.

Pineapple is a key economic resource in Ghana, but pineapple yields generally remain low. Yield losses occur due to water deficiency and pests during the crop development. Furthermore, we discovered that the market for irrigation advisory services is largely untapped, given that not much is being done to this respect in Ghana. Smallholder pineapple farmers do not irrigate at all and most commercial farms only practice supplementary irrigation or fertigation. This has mainly to do with the high irrigation costs and perceived drought resistance of pineapples.

Concept of the geo-service to assess and monitor water productivity for pineapple farms.

To assist in mitigating the high irrigation costs and to provide insight into potential yield gains by applying targeted irrigation, FutureWater is developing an irrigation advice geo-service that combines flying sensor imagery providing high-resolution information on crop growth status, and a crop growth model that uses this data to estimate crop water consumption, crop yield and water productivity. Yield gaps (difference between the actual yield and potential yield) can also be assessed and mapped.

Preliminary outcomes from the pilot study show a great potential for flying sensors to monitor crop growth status at the plot level. In contrast to satellite data, flying sensor imagery can detect individual plants and provide near-real time information about the condition of each plant. This information can be processed into a tailored irrigation advice at the plot-level, which can help the pineapple farmers save water and costs while being able to obtain higher yields.

Working closely with partners in the TWIGA consortium, FutureWater is looking forward to further develop this geo-service for sustainable agricultural growth in Africa.